Side-by-Side Pricing
| Plan | Slack | Microsoft Teams |
|---|---|---|
| Free | $0 — 90-day history, 10 integrations, 5GB storage | $0 — Chat, 60-min video, 5GB storage |
| Entry paid | Pro $8.75/user/mo ($87/yr) — Unlimited history, integrations, group video | Teams Essentials $4/user/mo ($48/yr) — 30-hr meetings, 10GB storage |
| Business | Business+ $18/user/mo ($180/yr) — SSO, advanced AI, compliance exports | M365 Business Basic $6/user/mo ($72/yr) — Web Office apps, 1TB storage |
| Enterprise | Enterprise Grid — custom pricing, HIPAA, unlimited workspaces | M365 Business Standard $12.50/user/mo ($150/yr) — Desktop Office apps |
Key insight: Microsoft 365 Business Basic ($6/user/mo) includes Teams, web Office apps, 1TB OneDrive, and Exchange email. Slack Pro alone is $8.75/user/mo. If you need Office apps anyway, Teams is effectively free.
Feature Comparison
| Feature | Slack | Teams |
|---|---|---|
| Third-party integrations | 2,600+ apps | Hundreds + deep M365 integration |
| Video conferencing | Huddles (light, up to 50) | Full meetings (up to 300–1,000) |
| File storage integration | Google Drive, Dropbox, OneDrive | SharePoint, OneDrive (native) |
| Workflow automation | Workflow Builder (built-in) | Power Automate (separate tool) |
| AI features | Slack AI (summaries, search) | Copilot for M365 ($30/user/mo extra) |
| Message threading | Excellent — core feature | Improving but still less intuitive |
| Performance / speed | Fast, lightweight feel | Can feel heavy, resource-intensive |
| Meeting recordings | No built-in (use Loom/Zoom) | Yes — with transcription |
| Phone system | No (use third-party) | Teams Phone (add-on) |
| Compliance | SOC 2, GDPR, ISO 27001, HIPAA (Grid) | SOC 2, GDPR, ISO 27001, HIPAA, FedRAMP |
Decision Framework
Choose Slack if:
- ✓You need the broadest third-party app ecosystem
- ✓Your team values fast, lightweight messaging UX
- ✓You don't use Microsoft 365 for docs and email
- ✓You rely heavily on channel-based communication
- ✓You're in the Salesforce ecosystem
Choose Teams if:
- ✓Your organization uses Microsoft 365
- ✓You need a combined chat + video conferencing solution
- ✓Meeting recordings with transcription are important
- ✓Budget is a primary concern (included in M365)
- ✓You need FedRAMP compliance
What Slack Does Better
Integration ecosystem. 2,600+ apps in Slack's marketplace. Jira, GitHub, Figma, Salesforce, Notion, and virtually every SaaS tool has a first-class Slack integration. Teams integrations are growing but narrower outside the Microsoft ecosystem.
Threading and channel organization. Slack's threaded conversations are more intuitive and less cluttered. Teams has threads but they feel bolted on rather than native. For teams with high message volume, Slack is easier to follow.
Performance. Slack feels snappier in day-to-day use. Teams can feel heavy, especially on machines already running other Microsoft apps. The Electron-based Teams app consumes significant system resources.
What Teams Does Better
Video conferencing. Teams is a full video conferencing platform — meetings for up to 300 people, recording with transcription, breakout rooms, Together Mode, and background blur. Slack Huddles are lightweight audio/video, not a Zoom replacement.
Microsoft 365 integration. Co-edit Word docs, share Excel files, access SharePoint libraries, and schedule via Outlook — all without leaving Teams. This deep integration is Teams' strongest advantage for Microsoft shops.
Total cost. Microsoft 365 Business Basic at $6/user/mo includes Teams, web Office apps, 1TB OneDrive, and Exchange email. Slack Pro alone is $8.75/user/mo without any of those extras.
Annual Cost at Three Team Sizes
| Team Size | Slack Pro | Teams (M365 Basic) |
|---|---|---|
| 10 users | $870/yr | $720/yr (includes Office + 1TB storage) |
| 50 users | $4,350/yr | $3,600/yr |
| 200 users | $17,400/yr | $14,400/yr |
If you're already paying for M365, Teams is included at no additional cost. Add Slack on top of M365 and you're effectively doubling your communication spend.
Migration Between the Two
Slack to Teams
Effort: Medium (1–2 weeks for a 50-person team). What transfers: Channel structure can be recreated. What breaks: Message history (export available but doesn't import into Teams), Slack-specific integrations, Workflow Builder automations, and Slack Connect shared channels with external partners.
Teams to Slack
Effort: Medium. What transfers: Channel structure and member list. What breaks: SharePoint file connections, Power Automate workflows, meeting recording library, and Teams-specific tabs and apps. Teams eDiscovery and compliance data stays in the Microsoft ecosystem.
Common Mistakes When Choosing
Paying for Slack when you already have M365
Teams is included with Microsoft 365. Paying $8.75/user/mo for Slack on top of an existing M365 subscription means you're paying twice for messaging. Unless Slack's integration ecosystem is critical, this is wasted spend.
Assuming Teams replaces Zoom
Teams meetings are good but not as polished as Zoom for external-facing webinars and large events. For internal meetings with M365 users, Teams is excellent. For client-facing calls where participants may not have Teams, Zoom is smoother.
Ignoring Slack's 90-day free tier limit
Slack Free hides messages older than 90 days. This means losing institutional knowledge every quarter. If you won't pay for Pro, Teams Free (with unlimited history) or Discord (free, unlimited history) may be better alternatives.
Frequently Asked Questions
Can Slack and Teams integrate with each other?
Not natively in a meaningful way. Some organizations run both (Slack for engineering, Teams for company-wide comms), but messages don't bridge between them without third-party tools.
Is Teams really free?
Microsoft Teams (Free) is genuinely free with unlimited messaging history, 60-minute video meetings, and 5GB storage. Teams Essentials ($4/user/mo) adds longer meetings, 10GB storage, and meeting recordings.
What about Discord for business?
Discord is free with unlimited messaging and decent voice channels. It's viable for startups and dev teams but lacks enterprise compliance (SSO, DLP, audit logs), formal integrations with business tools, and feels unprofessional for client-facing communication.
Does Slack AI compete with Copilot?
Slack AI focuses on message summaries, thread catch-up, and search. M365 Copilot ($30/user/mo extra) works across Word, Excel, PowerPoint, and Teams for content generation. They solve different problems at very different price points.
Which is more secure?
Both offer enterprise-grade security. Teams has a slight edge with FedRAMP certification and deeper integration with Azure Active Directory and Microsoft Entra. Slack Enterprise Grid offers HIPAA compliance, EKM (Enterprise Key Management), and GovSlack for government.
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