Microsoft 365 vs Slack 2026: Full Comparison
Microsoft 365 is a comprehensive productivity suite with email, Office apps, and Teams collaboration, while Slack is a specialized messaging and workflow platform. Microsoft 365 offers more integrated tools under one license, whereas Slack excels as a dedicated communication hub that integrates with 2,300+ third-party apps.
Microsoft 365
Integrated productivity and collaboration suite with Office apps, email, and Teams.
Enterprises with existing Windows infrastructure, organizations needing comprehensive productivity tools, teams requiring robust email and document management
Slack
Cloud-based team messaging platform with 2,000+ integrations and 750,000+ active workspaces.
Tech-forward teams, startups using best-of-breed tools, organizations prioritizing communication speed and workflow automation
Quick Answer
AI SummaryMicrosoft 365 is a comprehensive productivity suite with email, Office apps, and Teams collaboration, while Slack is a specialized messaging and workflow platform. Microsoft 365 offers more integrated tools under one license, whereas Slack excels as a dedicated communication hub that integrates with 2,300+ third-party apps.
Our Verdict
AI-assistedChoose Microsoft 365 if you need a unified productivity ecosystem with email, document creation, video conferencing, and collaboration in one platform, especially for organizations using Windows. Choose Slack if your team prioritizes streamlined messaging, rapid communication, and deep integrations with best-of-breed specialized tools across your existing tech stack.
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Choose Microsoft 365 if
Enterprises with existing Windows infrastructure, organizations needing comprehensive productivity tools, teams requiring robust email and document management
Choose Slack if
Best pickTech-forward teams, startups using best-of-breed tools, organizations prioritizing communication speed and workflow automation
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Key Differences at a Glance
- Primary Function:✓ Microsoft 365 wins(Comprehensive productivity suite (email, docs, spreadsheets, presentations, collaboration) vs Dedicated team messaging and communication platform)
- Monthly Cost Per User (Standard Plans):✓ Slack wins($7.25 (Slack Pro, annual billing) vs $12.50 (Microsoft 365 Business Standard))
- Built-in Email System:✓ Microsoft 365 wins(Yes (Outlook included) vs No (third-party integration required))
Key Facts & Figures
144 numeric metrics compared
| Metric | Microsoft 365 | Slack | Ratio |
|---|---|---|---|
| Monthly Cost Per User (Entry Plan)(USD) | $6 | — | — |
| Cloud Storage Included (Basic)(GB) | 1,000GB (1TB) | — | — |
| Integrated Business Applications(applications) | 12+ | — | — |
| Global Market Share(%) | 45-50% | 65% | |
| Free Trial Period(days) | 30 days | — | — |
| Concurrent Excel Edit Capacity(users) | 1M+ | — | — |
| Annual Cost (Single User)(USD) | $69 (Personal) to $100 (Family) | — | — |
| Excel Functions Available(count) | 400+ | — | — |
| Maximum Simultaneous Collaborators(users) | 100+ | — | — |
| Real-Time Change Tracking Options(count) | 30+ | — | — |
| Cost Per User (Monthly)(USD) | $6 (Business Basic) | — | — |
| Cloud Storage Included(GB) | 1,000 GB (OneDrive) | — | — |
| Real-Time Collaboration Latency(milliseconds) | ~300 ms for co-authoring sync | — | — |
| Starting Monthly Cost Per User(USD) | $6.00 | — | — |
| Cloud Storage (Standard Plan)(GB) | 1,000 GB | — | — |
| Email Mailbox Capacity(GB) | 100 GB | — | — |
| Paid Users Globally(millions) | 60+ | — | — |
| Maximum Team Members (Free Tier)(users) | Limited to 30 days free trial | — | — |
| Language Support(primary languages) | 119 | — | — |
| Enterprise Compliance Certifications(count) | SOC 2 Type II, HIPAA, FedRAMP, ISO 27001, GDPR, CCPA | — | — |
| Support Response Time (Paid)(hours) | 1 hour (Premium Support) | — | — |
| Annual Cost Per User(USD) | $69-$120 | — | — |
| Microsoft Office File Compatibility(%) | 99% fidelity | — | — |
| Enterprise Security Certifications(count) | SOC 2, HIPAA, GDPR, FedRAMP | SOC 2 Type II, ISO 27001, FedRAMP | — |
| Typical Installation Size(MB) | Web-based (minimal local footprint) | — | — |
| Starting Monthly Price per User(USD) | $6 | — | — |
| Premium/Advanced Tier Price(USD/month) | $22 (Microsoft 365 Apps for enterprise) | — | — |
| Included Email Mailbox Capacity(GB) | 50 | — | — |
| OneDrive Cloud Storage per User(GB) | 1,000 | — | — |
| User Learning Curve (1-10 scale, 10=hardest)(scale) | 2-3 (intuitive Office interface) | — | — |
| Included Cloud Storage(GB) | 1,024 GB (1TB) | — | — |
| Simultaneous Devices(devices) | 5 devices per subscription | — | — |
| Microsoft Office File Format Compatibility(percent) | 99.9% native support | — | — |
| Supported File Formats(count) | 45+ major formats | — | — |
| Monthly Cost Per User (Standard Tier, Annual Billing)(USD) | $12.50 | $7.25 | |
| Cloud Storage Included Per User(GB) | 1,000 GB (OneDrive) | 0 GB (integrations only) | |
| Maximum Video Conference Participants (Standard Plan)(participants) | 300 | 2 | |
| Third-Party App Integrations Available(integrations) | 450+ | 2,300+ | |
| App Integrations(count) | 2,600+ | 2,600+ | |
| Paid Starting Price(USD/user/mo) | $7.25 | $7.25 | |
| Standalone Monthly Pricing (Pro Tier)(USD per user per month) | $7.25 | $7.25 | |
| Annual Cost per User (Pro Tier)(USD) | $87 (billed yearly) | $87 (billed yearly) | |
| Third-Party App Integrations(apps) | 2,400+ | 2,400+ | |
| Video Meeting Capacity(participants) | Up to 2,000 (with paid plan) | Up to 2,000 (with paid plan) | |
| Mobile App Feature Parity(%) | 95% | 95% | |
| Monthly Cost per 20-Person Team(USD) | $3,600 (Pro plan at $15/user) | $3,600 (Pro plan at $15/user) | |
| Free Trial Duration(days) | 7 days | 7 days | |
| Daily Active Users Worldwide(millions) | 20+ million | 20+ million | |
| Message History Retention on Free Plan(count) | 10,000 most recent | 10,000 most recent | |
| Base Monthly Cost Per User(USD) | $8.25 (Pro plan, min 3 users) | $8.25 (Pro plan, min 3 users) | |
| Free Tier Meeting Participant Limit(participants) | Unlimited (Slack Huddles for video limited to 50 participants) | Unlimited (Slack Huddles for video limited to 50 participants) | |
| Asynchronous Communication Strength(scale 1-5) | 5 out of 5 (core feature with channels, threads, and history) | 5 out of 5 (core feature with channels, threads, and history) | |
| Google Workspace Integration Level | 2 out of 5 (available via integration, not native) | 2 out of 5 (available via integration, not native) | |
| AI Features Count (2026)(features) | 30+ (CRM tools, meeting summaries, automation, SlackBot enhancements) | 30+ (CRM tools, meeting summaries, automation, SlackBot enhancements) | |
| Base Monthly Cost Per User(USD) | $7.25 | $7.25 | |
| Business+ Tier Monthly Cost Per User(USD) | $12.50 | $12.50 | |
| Available Integrations(integrations) | 2000+ | 2000+ | |
| Price Stability (2024-2026)(months) | No increases for 33 months | No increases for 33 months | |
| Free Tier Cost(USD) | Free | Free | |
| Pro/Standard Monthly Cost(USD per user/month) | $7.25 | $7.25 | |
| Third-party Integrations(integrations) | 2000+ | 2000+ | |
| Minimum Monthly Cost Per User(USD) | $7.25 | $7.25 | |
| Third-Party Integrations Available(count) | 2,000+ | 2,000+ | |
| Years Price Stable (2026)(months) | 33+ months | 33+ months | |
| Native Integrations Available(integrations) | 2200+ | 2200+ | |
| Pro Plan Annual Cost(USD) | $150 (billed monthly) | $150 (billed monthly) | |
| Free Tier Message History Retention(days) | 90 days | 90 days | |
| AI Transcription Languages Supported(languages) | 0 (not native feature) | 0 (not native feature) | |
| Enterprise Uptime SLA(percent) | 99.99% | 99.99% | |
| User Workspace Limit (Free Tier)(workspaces) | 1 workspace | 1 workspace | |
| Maximum Meeting Participants (Free)(participants) | 3 participants | 3 participants | |
| Pro Plan Monthly Cost (Annual Billing)(USD per user) | $8.75 | $8.75 | |
| Available Integrations(count) | 2,400+ | 2,400+ | |
| Monthly Cost (Pro Plan)(USD) | $12.50 per user/month | $12.50 per user/month | |
| Free Message History(days) | 90 days maximum | 90 days maximum | |
| Voice Audio Codec Quality(kHz) | 16 kHz | 16 kHz | |
| Third-Party Integrations(integrations) | 2000+ integrations | 2000+ integrations | |
| Maximum Video Call Participants(people) | 15 participants | 15 participants | |
| Total Registered Users(millions) | 750 million | 750 million | |
| Enterprise Plan Monthly Cost Per User(USD) | $12.50 | $12.50 | |
| Free Plan Message History Retention(days) | 90 days | 90 days | |
| Third-Party Integrations Available(count) | 2,300+ integrations | 2,300+ integrations | |
| Paid Plan Starting Price(USD/month) | $7.25 | $7.25 | |
| Cloud Storage (Base Plan)(GB) | 10 GB | 10 GB | |
| Monthly Cost Per User(USD) | $8-12.50 (Pro/Business+) | $8-12.50 (Pro/Business+) | |
| Active Workspaces(workspaces) | 750,000+ | 750,000+ | |
| Message History Searchable(years) | 10 years standard | 10 years standard | |
| Workflow Automation Steps(built-in steps) | 50+ | 50+ | |
| Native App Integrations Available(count) | 2,400+ apps | 2,400+ apps | |
| Monthly Cost (Pro Plan, 50 users)(USD) | $412.50/month | $412.50/month | |
| Paid Workspaces/Users (Enterprise Adoption)(workspaces) | 750,000+ paid workspaces | 750,000+ paid workspaces | |
| Monthly Cost (10 Users, Annual)(USD) | $150/month ($1,800/year) | $150/month ($1,800/year) | |
| Pre-built Integrations(operators) | 2,400+ integrations | 2,400+ integrations | |
| Message History on Free Plan(days) | 90-day limited access | 90-day limited access | |
| Active Global Workspaces/Deployments(count) | 750,000+ active workspaces | 750,000+ active workspaces | |
| Uptime SLA Guarantee(percentage) | 99.99% | 99.99% | |
| Price Per User Per Month (Pro/Standard)(USD) | $12.50/user (Pro plan) | $12.50/user (Pro plan) | |
| Base Monthly Cost (10-person team)(USD) | $80-150 | $80-150 | |
| Cost for 50-person team(USD/month) | $400-750 | $400-750 | |
| Real-time Messaging Speed(ms (message delivery latency)) | 50-100ms (instant) | 50-100ms (instant) | |
| File Storage Included(GB) | 5GB (Free), varies by plan | 5GB (Free), varies by plan | |
| Setup Time for New Team(hours) | 0.5-1 hour | 0.5-1 hour | |
| Max Video Conference Participants(people) | 1000 | 1000 | |
| Voice Codec Quality Rating(score (1-10)) | 7.5 | 7.5 | |
| Time to Deploy(hours) | 3-7 | 3-7 | |
| Uptime Guarantee(percent) | 99.99% | 99.99% | |
| Pro Plan Monthly Cost(USD) | $8.75 | $8.75 | |
| Video Conference Max Participants(participants) | 150 | 150 | |
| Free Tier File Storage(GB per user) | 1 GB shared workspace | 1 GB shared workspace | |
| Message Search History (Free Tier)(days) | 90 days | 90 days | |
| Annual Subscription Cost (Pro, 100 users)(USD) | $10,500 | $10,500 | |
| Desktop App Memory Usage(MB) | 280 MB | 280 MB | |
| Monthly subscription cost (Pro plan)(USD per user) | $12.50 | $12.50 | |
| Native third-party integrations(count) | 100+ | 100+ | |
| Message Search Response Time(seconds) | 2-4 seconds | 2-4 seconds | |
| User interface satisfaction rating(out of 10) | 9.2/10 | 9.2/10 | |
| Maximum video call participants (free tier)(people) | 100 participants | 100 participants | |
| Service uptime SLA guarantee(percent) | 99.99% | 99.99% | |
| Message history retention (free plan)(days) | 90 days searchable | 90 days searchable | |
| Enterprise app marketplace size(applications) | 2,000+ apps (Slack App Directory) | 2,000+ apps (Slack App Directory) | |
| Team Size Cost Efficiency Threshold(team members) | Cost-effective until ~12 users | Cost-effective until ~12 users | |
| Message History Searchability(months) | 90 days (Free/Pro), unlimited with Enterprise | 90 days (Free/Pro), unlimited with Enterprise | |
| Average User Adoption Time(days) | 1-3 days | 1-3 days | |
| Global Active Users(millions) | 750+ million messages daily across 750k+ organizations | 750+ million messages daily across 750k+ organizations | |
| Monthly Subscription Cost (Pro/Standard)(USD) | $8.25 | $8.25 | |
| Message Delivery Latency(milliseconds) | <100ms | <100ms | |
| File Upload Limit(GB) | 20GB | 20GB | |
| Message History Retention (Free Tier)(days) | 90 days | 90 days | |
| G2 Ease of Use Rating (2024)(stars) | 4.5/5 | 4.5/5 | |
| Video Meeting Participant Limit(participants) | 2000 | 2000 | |
| Pro Plan Monthly Cost Per User(USD) | $12.50 | $12.50 | |
| File Storage Per User(GB) | 100 (workspace) | 100 (workspace) | |
| Free Group Video Call Duration Limit(minutes) | 40 | 40 | |
| Maximum Video Conference Participants (Free)(people) | Limited (typically 3-4) | Limited (typically 3-4) | |
| G2 User Interface Rating(out of 5) | 4.6/5 (12,400 reviews) | 4.6/5 (12,400 reviews) | |
| Daily Active Users(millions) | 21 million | 21 million | |
| Message History (Free Plan)(days) | 90 days | 90 days | |
| Cost Per User (Annual, Lowest Paid Tier)(USD/month) | $8/month | $8/month | |
| Organizations Using Platform(count (thousands)) | 750,000+ | 750,000+ | |
| Message Search History(messages) | 10,000 (free tier); unlimited (paid) | 10,000 (free tier); unlimited (paid) | |
| Base Cost per User/Month(USD) | $8.99 | $8.99 | |
| Native Integrations(count) | 2,000+ | 2,000+ | |
| Active Workspaces/Deployments(count) | 750,000 | 750,000 | |
| iOS App Rating(stars) | 4.7 | 4.7 |
Sourced from publicly available data ·
Key Differences
7 attributes compared head-to-head
- Comprehensive productivity suite (email, docs, spreadsheets, presentations, collaboration)(winner)Primary FunctionDedicated team messaging and communication platform
- $12.50 (Microsoft 365 Business Standard)Monthly Cost Per User (Standard Plans)$7.25 (Slack Pro, annual billing)(winner)
- Yes (Outlook included)(winner)Built-in Email SystemNo (third-party integration required)
- 450+ native integrationsThird-Party App Integrations2,300+ available integrations(winner)
- 1 TB (OneDrive)(winner)Cloud Storage Per UserFile sharing via third-party apps
- 300 participants (Teams)(winner)Video Conferencing Participants (Free Plan)Not available (Slack Calls limited to direct messages)
- Unlimited search in Outlook(winner)Message Search History (Free Plan)Last 90 days only
- Primary Function
Microsoft 365
Comprehensive productivity suite (email, docs, spreadsheets, presentations, collaboration)(winner)
Slack
Dedicated team messaging and communication platform
- Monthly Cost Per User (Standard Plans)
Microsoft 365
$12.50 (Microsoft 365 Business Standard)
Slack
$7.25 (Slack Pro, annual billing)(winner)
- Built-in Email System
Microsoft 365
Yes (Outlook included)(winner)
Slack
No (third-party integration required)
- Third-Party App Integrations
Microsoft 365
450+ native integrations
Slack
2,300+ available integrations(winner)
- Cloud Storage Per User
Microsoft 365
1 TB (OneDrive)(winner)
Slack
File sharing via third-party apps
- Video Conferencing Participants (Free Plan)
Microsoft 365
300 participants (Teams)(winner)
Slack
Not available (Slack Calls limited to direct messages)
- Message Search History (Free Plan)
Microsoft 365
Unlimited search in Outlook(winner)
Slack
Last 90 days only
Full Comparison
| Attribute | Slack | |
|---|---|---|
| Monthly Cost (Standard Tier)(USD/user/month) | $12.50 | — |
| Monthly Cost Per User (Entry Plan)(USD) | $6 | — |
| Annual Cost (Single User)(USD) | $69 (Personal) to $100 (Family) | — |
| Cost Per User (Monthly)(USD) | $6 (Business Basic) | — |
| Starting Monthly Cost Per User(USD) | $6.00 | — |
Show 34 more attributesAnnual Cost Per User(USD) $69-$120 — Starting Monthly Price per User(USD) $6 — Premium/Advanced Tier Price(USD/month) $22 (Microsoft 365 Apps for enterprise) — Monthly Cost Per User (Standard Tier, Annual Billing)(USD) $12.50 $7.25 Standalone Monthly Pricing (Pro Tier)(USD per user per month) $7.25 — Annual Cost per User (Pro Tier)(USD) $87 (billed yearly) — Monthly Cost per 20-Person Team(USD) $3,600 (Pro plan at $15/user) — Base Monthly Cost Per User(USD) $8.25 (Pro plan, min 3 users) — Base Monthly Cost Per User(USD) $7.25 — Business+ Tier Monthly Cost Per User(USD) $12.50 — Price Stability (2024-2026)(months) No increases for 33 months — Free Tier Cost(USD) Free — Pro/Standard Monthly Cost(USD per user/month) $7.25 — Minimum Monthly Cost Per User(USD) $7.25 — Years Price Stable (2026)(months) 33+ months — Pro Plan Annual Cost(USD) $150 (billed monthly) — Pro Plan Monthly Cost (Annual Billing)(USD per user) $8.75 — Monthly Cost (Pro Plan)(USD) $12.50 per user/month — Enterprise Plan Monthly Cost Per User(USD) $12.50 — Paid Plan Starting Price(USD/month) $7.25 — Monthly Cost Per User(USD) $8-12.50 (Pro/Business+) — Monthly Cost (Pro Plan, 50 users)(USD) $412.50/month — Monthly Cost (10 Users, Annual)(USD) $150/month ($1,800/year) — Price Per User Per Month (Pro/Standard)(USD) $12.50/user (Pro plan) — Base Monthly Cost (10-person team)(USD) $80-150 — Cost for 50-person team(USD/month) $400-750 — Pro Plan Monthly Cost(USD) $8.75 — Annual Subscription Cost (Pro, 100 users)(USD) $10,500 — Monthly subscription cost (Pro plan)(USD per user) $12.50 — Team Size Cost Efficiency Threshold(team members) Cost-effective until ~12 users — Monthly Subscription Cost (Pro/Standard)(USD) $8.25 — Pro Plan Monthly Cost Per User(USD) $12.50 — Cost Per User (Annual, Lowest Paid Tier)(USD/month) $8/month — Base Cost per User/Month(USD) $8.99 — | ||
| Global Paid Seats (2026)(millions) | 446M | — |
| Active Workspaces(workspaces) | 750,000+ | — |
| Active Workspaces/Deployments(count) | 750,000 | — |
| Market Share(percentage) | ~58% | — |
| Global Market Share(%) | 45-50% | 65%(winner) |
| Paid Users Globally(millions) | 60+ | — |
| AI Assistant Availability | Copilot (premium only) | — |
| AI Assistant Integration | Copilot included (most plans) | — |
| AI Assistant Capability | Slack AI (optional on paid plans) | — |
| AI Transcription Languages Supported(languages) | 0 (not native feature) | — |
| AI Meeting Assistant | Slack AI (search, summarization, drafting) | — |
| IT Management Burden(user satisfaction) | Complex enterprise setup | — |
| Desktop App Integration | Full Office suite included | — |
| Integrated Business Applications(applications) | 12+ | — |
| Native CRM Included | No (Dynamics 365 separate) | — |
| Excel Functions Available(count) | 400+ | — |
| Real-Time Change Tracking Options(count) | 30+ | — |
Show 39 more attributesDatabase Relations Support(capability) Basic lookup fields in Excel — Native Email Functionality(yes/no) Yes (Outlook with 50 GB inbox) — Built-in AI Features Copilot (separate $20/month add-on) — Cloud Storage (Standard Plan)(GB) 1,000 GB — Email Mailbox Capacity(GB) 100 GB — Office Suite (Word, Excel, PowerPoint) Included(null) Yes (all included) — Simultaneous Devices(devices) 5 devices per subscription — Cloud Storage Included Per User(GB) 1,000 GB (OneDrive) 0 GB (integrations only) Maximum Video Conference Participants (Standard Plan)(participants) 300 2 Message Search History Retention (Free Plan)(days) Unlimited — App Integrations(count) 2,600+ — Video Meeting Capacity(participants) Up to 2,000 (with paid plan) — Native Office Integration Limited (third-party connectors) — AI Copilot Features Slack AI (summarization, search, assisted writing) — Message History Retention on Free Plan(count) 10,000 most recent — Free Tier Meeting Participant Limit(participants) Unlimited (Slack Huddles for video limited to 50 participants) — Native Video Conferencing Huddles for brief video, limited to 50 participants; requires external tool for full conferencing — Meeting Recording & Auto-Transcription Not native; requires integration with Otter.ai or similar third-party services — Asynchronous Communication Strength(scale 1-5) 5 out of 5 (core feature with channels, threads, and history) — Third-Party Integrations Available(count) 2,000+ — Enterprise AI Features Advanced AI assistant, smart summaries, automation — Native Integrations Available(integrations) 2200+ — Free Message History(days) 90 days maximum — Third-Party Integrations(integrations) 2000+ integrations — Free Plan Message History Retention(days) 90 days — Free Plan External Guest Collaboration(capacity) Unlimited external guests via workspace invite — Email Service Included No — Message History Searchable(years) 10 years standard — Workflow Automation Steps(built-in steps) 50+ — Pre-built Integrations(operators) 2,400+ integrations — Message History on Free Plan(days) 90-day limited access — Message History Retention(status) 10,000 messages (free); unlimited (paid) — Built-in Project Management(status) No (requires integrations) — Max Video Conference Participants(people) 1000 — Video Conference Max Participants(participants) 150 — Message Search History (Free Tier)(days) 90 days — Message Search Speed (Free Tier)(indexing scope) All messages indexed instantly — Message History Retention (Free Tier)(days) 90 days — Video Meeting Participant Limit(participants) 2000 — | ||
| Real-Time Collaboration Speed(relative rating) | Comprehensive, moderate | — |
| Real-Time Collaboration Latency(milliseconds) | ~300 ms for co-authoring sync | — |
| Typical Installation Size(MB) | Web-based (minimal local footprint) | — |
| Real-time Data Refresh (Premium)(seconds) | Not available | — |
| Message Search Speed(seconds) | Excellent - optimized search indexing | — |
Show 6 more attributesVoice Audio Codec Quality(kHz) 16 kHz — Maximum Video Call Participants(people) 15 participants — Real-time Messaging Speed(ms (message delivery latency)) 50-100ms (instant) — Desktop App Memory Usage(MB) 280 MB — Message Search Response Time(seconds) 2-4 seconds — Message Delivery Latency(milliseconds) <100ms — | ||
| Enterprise Security (Intune/Advanced Tools) | Industry-leading with Intune E3/E5 | — |
| SSO (Single Sign-On) Availability | Standard in Business plans ($6+/user) | — |
| Enterprise Compliance Certifications(count) | SOC 2 Type II, HIPAA, FedRAMP, ISO 27001, GDPR, CCPA | — |
| Enterprise Security Certifications(count) | SOC 2, HIPAA, GDPR, FedRAMP | SOC 2 Type II, ISO 27001, FedRAMP |
| GDPR & Data Sovereignty Compliance | Compliant but data on Salesforce servers | — |
Show 2 more attributesEnd-to-End Encryption Available DMs only, Enterprise+ plan — End-to-End Encryption Default Not available — | ||
| Cloud Storage Included (Basic)(GB) | 1,000GB (1TB) | — |
| Cloud Storage Included(GB) | 1,000 GB (OneDrive) | — |
| OneDrive Cloud Storage per User(GB) | 1,000 | — |
| Included Cloud Storage(GB) | 1,024 GB (1TB) | — |
| Storage Per User (Standard Plan)(GB) | Variable by plan | — |
Show 6 more attributesCloud Storage (Base Plan)(GB) 10 GB — File Storage Included(GB) 5GB (Free), varies by plan — Free Tier File Storage(GB per user) 1 GB shared workspace — Message history retention (free plan)(days) 90 days searchable — File Upload Limit(GB) 20GB — File Storage Per User(GB) 100 (workspace) — | ||
| Free Trial Period(days) | 30 days | — |
| Free Trial Duration(days) | 7 days | — |
| Concurrent Excel Edit Capacity(users) | 1M+ | — |
| Maximum Simultaneous Collaborators(users) | 100+ | — |
| Real-Time Co-Authoring Support | Yes (unlimited simultaneous users) | — |
| Included Email Mailbox Capacity(GB) | 50 | — |
| Supported Operating Systems | Windows, macOS, iOS, Android, Web | — |
| Microsoft Office File Compatibility(%) | 99% fidelity | — |
| Available Platforms | Windows, Mac, iOS, Android, Web | — |
| Microsoft Office File Format Compatibility(percent) | 99.9% native support | — |
| Supported File Formats(count) | 45+ major formats | — |
| Offline Editing Capability | Full support | — |
| Maximum Meeting Participants(participants) | Unlimited group chats | — |
| Built-in Task Management(features) | No: messaging-only, requires integrations | — |
| Message History Searchability(months) | 90 days (Free/Pro), unlimited with Enterprise | — |
| Enterprise Active Directory Integration | Yes, native support | — |
| Maximum Team Size Per Plan(users) | Unlimited (per subscription) | — |
| Maximum Team Members (Free Tier)(users) | Limited to 30 days free trial | — |
| Users Per Workspace(count) | Unlimited | — |
| Offline Desktop Editing(yes/no) | Yes (full Office suite offline) | — |
| Mobile Platform Support(platforms) | iOS, Android, Windows Phone | — |
| Language Support(primary languages) | 119 | — |
| Third-Party App Integrations Available(integrations) | 450+ | 2,300+(winner) |
| Available Integrations(integrations) | 2000+ | — |
| Support Response Time (Paid)(hours) | 1 hour (Premium Support) | — |
| AI-Powered Features(count) | Copilot, Designer, smart suggestions | — |
| Data Sources Supported(count) | 20+ (via Excel integrations) | — |
| Third-Party App Integrations(apps) | 2,400+ | — |
| Google Workspace Native Integration | Limited (requires custom setup) | — |
| Native third-party integrations(count) | 100+ | — |
| Native Microsoft 365 Integration(integration level) | API-based (basic) | — |
| Average Dashboard Creation Time(hours) | 4-8 (without Power BI) | — |
| User Learning Curve (1-10 scale, 10=hardest)(scale) | 2-3 (intuitive Office interface) | — |
| Setup Time for New Team(hours) | 0.5-1 hour | — |
| Paid Starting Price(USD/user/mo) | $7.25 | — |
| Mobile App Feature Parity(%) | 95% | — |
| Mobile App Type | Native iOS/Android with feature-parity | — |
| Daily Active Users Worldwide(millions) | 20+ million | — |
| Self-Hosting Available(boolean) | No | — |
| Self-Hosted/On-Premises Option | No (cloud-only) | — |
| Google Workspace Integration Level | 2 out of 5 (available via integration, not native) | — |
| AI Features Count (2026)(features) | 30+ (CRM tools, meeting summaries, automation, SlackBot enhancements) | — |
| Deployment Options | Cloud-based SaaS only | — |
| Deployment Options(types) | Cloud SaaS only | — |
| Third-party Integrations(integrations) | 2000+ | — |
| Available Integrations(count) | 2,400+ | — |
| Third-Party Integrations Available(count) | 2,300+ integrations | — |
| Native Integrations(count) | 2,000+ | — |
| AI Features (2026) | Workflow automation, search enhancement | — |
| Real-Time Translation | Not available | — |
| Asynchronous Communication | Optimized with threads and archives | — |
| Zoom Rooms Cost(USD per room/month) | N/A | — |
| Workflow Automation Complexity | Advanced with conditional logic | — |
| Open Source | No, proprietary | — |
| Maximum Video Length (Free Tier)(minutes) | N/A | — |
| Maximum Video Resolution(pixels) | Requires 3rd party | — |
| Free Tier Message History Retention(days) | 90 days | — |
| Enterprise Uptime SLA(percent) | 99.99% | — |
| Uptime SLA Guarantee(percentage) | 99.99% | — |
| Uptime Guarantee(percent) | 99.99% | — |
| Service uptime SLA guarantee(percent) | 99.99% | — |
| User Workspace Limit (Free Tier)(workspaces) | 1 workspace | — |
| Maximum Meeting Participants (Free)(participants) | 3 participants | — |
| Maximum Meeting Participants (Paid)(participants) | Unlimited (slide deck view only) | — |
| Free Plan Message History(months) | 90 days | — |
| FedRAMP Authorization(boolean) | No | — |
| HIPAA Compliance Certified | Yes (Business+ plan required) | — |
| SOC 2 Type II Certified | Yes | — |
| Custom Workflow Automation | Advanced (Workflow Builder, automations) | — |
| Total Registered Users(millions) | 750 million | — |
| Daily Posts Published (Organic)(millions) | N/A | — |
| Threading Model | Channel-based threads (contextual loss in active channels) | — |
| Open Source | Proprietary (closed-source) | — |
| Native Video/Audio Calls | Yes (Slack Huddles) | — |
| Native App Integrations Available(count) | 2,400+ apps | — |
| Paid Workspaces/Users (Enterprise Adoption)(workspaces) | 750,000+ paid workspaces | — |
| Active Global Workspaces/Deployments(count) | 750,000+ active workspaces | — |
| Source Code Availability | Proprietary/closed | — |
| Voice Codec Quality Rating(score (1-10)) | 7.5 | — |
| Time to Deploy(hours) | 3-7 | — |
| Learning Curve(hours to proficiency) | 2 | — |
| Monthly Active Users(millions) | 0.75 million | — |
| User interface satisfaction rating(out of 10) | 9.2/10 | — |
| Average User Adoption Time(days) | 1-3 days | — |
| G2 Ease of Use Rating (2024)(stars) | 4.5/5 | — |
| G2 User Interface Rating(out of 5) | 4.6/5 (12,400 reviews) | — |
| iOS App Rating(stars) | 4.7 | — |
| Maximum video call participants (free tier)(people) | 100 participants | — |
| Free Group Video Call Duration Limit(minutes) | 40 | — |
| Maximum Video Conference Participants (Free)(people) | Limited (typically 3-4) | — |
| Enterprise app marketplace size(applications) | 2,000+ apps (Slack App Directory) | — |
| Global Active Users(millions) | 750+ million messages daily across 750k+ organizations | — |
| Message Search Capability(text) | Full-text indexed across all messages | — |
| Daily Active Users(millions) | 21 million | — |
| End-to-End Encryption | Partial (DMs only, beta feature) | — |
| Message History (Free Plan)(days) | 90 days | — |
| Message Search History(messages) | 10,000 (free tier); unlimited (paid) | — |
| Self-Hosting Capability | Not available | — |
| Organizations Using Platform(count (thousands)) | 750,000+ | — |
| GDPR Compliance | Certified (SOC 2 Type II, GDPR) | — |
| GitHub Stars (Community)(stars) | N/A (proprietary) | — |
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Pros & Cons
10 pros·6 cons across both
Microsoft 365
Pros
- Includes Outlook email with full Exchange integration
- 1 TB OneDrive cloud storage per user included
- Teams video conferencing supports up to 300 participants
- Office apps (Word, Excel, PowerPoint) with real-time co-authoring
- Seamless Windows and Active Directory integration
Cons
- Higher price point ($12.50/user/month) than Slack at scale
- Teams chat interface less intuitive than Slack for notification management
- Smaller third-party integration ecosystem (450 vs Slack's 2,300)
Slack
Pros
- Lower cost ($7.25/user/month annual) with affordable free tier
- 2,300+ app integrations for custom workflows and automation
- Superior user interface designed specifically for chat and collaboration
- Powerful search and threading keep conversations organized
- Works seamlessly across Windows, Mac, Linux, iOS, Android
Cons
- Free plan limits message history to last 90 days
- Requires separate tools for email, video conferencing, document storage
- No built-in video conferencing; depends on third-party integration (Zoom, Google Meet)
Frequently Asked Questions
5 questions
Slack cannot fully replace Microsoft 365 because it lacks email, document creation (Word/Excel/PowerPoint), and robust video conferencing. However, you can integrate Slack with Google Workspace or Microsoft 365 to use Slack for communication while maintaining your productivity tools. Many companies use both together rather than one replacing the other.
Resources & Learn More
Curated sources to dive deeper
Where to Buy
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Wikipedia
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