Slack vs Microsoft Teams: which is right for a small business?

How do Slack and Microsoft Teams differ in approach?

Slack is a chat app first, and Teams is a meetings and chat app that comes inside Microsoft 365. Slack organises work into channels for each project, topic or team and connects over 2,600 apps from its Marketplace; Teams is built around the meeting, the call and the Office files you already keep in Microsoft.

That difference decides most small-business choices. A team that writes more than it talks, and runs a dozen tools, tends to prefer Slack's channels, threads, workflows and search. A team that spends its day on calls with customers, or already pays for Outlook, Word and Excel, usually finds Teams is already there and already paid for.

How much do Slack and Teams cost for a small team?

Teams costs less per paid user, and Slack costs less to start. Teams Essentials is $4 a user a month on a yearly subscription. Microsoft 365 Business Basic with Teams is $7 a user paid yearly and adds business email on your domain, the web and mobile Office apps and 1 TB of storage per user.

Slack Pro is $7.25 a user a month billed yearly, or $8.75 billed monthly. Business+ is $15 a user billed yearly, or $18 monthly, and adds Slack's Advanced AI, single sign-on and user provisioning. Enterprise+ is priced by Slack's sales team.

Slack has the free plan: Free stays at $0 with 90 days of history, up to 10 apps, 1:1 huddles and 1:1 external messages. Microsoft offers a separate free Teams edition; its business page lists paid plans and a one-month trial that needs a card. New Slack teams buying monthly Pro or Business+ online in their first seven days also get 50% off for three months, which is a promotion rather than the price.

How does the AI compare?

Slack includes its AI in every plan's price; Microsoft puts Copilot in Teams in its higher plans. Slack's plan cards say Free and Pro have Basic AI (conversation summaries, Slackbot, AI search, daily recaps and file summaries), Business+ has Advanced AI, and Enterprise+ adds enterprise search. Slack shows no separate AI price, and says plan limits apply.

Teams includes live captions and meeting transcription in the plans that have Teams, and Copilot Chat comes with eligible business subscriptions. Copilot inside Teams chats, calls and catch-up needs a Microsoft 365 plan "with Copilot", such as Business Standard with Copilot at $23.50 a user a month paid yearly, and a Teams license. If your AI wish is "tell me what I missed in the meeting", Teams' transcripts do it well; if it's "summarise the channels I skipped", Slack's is included from Free.

Which works better with customers and contractors?

Both let outside people in, in different ways. Slack Connect shares channels between companies: 1:1 on Free, and up to 250 organisations on paid plans. It works best when your clients use Slack too. Teams Essentials includes unlimited chat with coworkers and customers, including guest access, and Microsoft Teams Phone Standard adds cloud calling for $10.00 a user a month paid yearly, for teams that want their phone line in the same app.

Which connects better to AI agents?

Slack has the more direct route. Its MCP server lets AI clients such as Claude.ai, Claude Code, Perplexity and Cursor search messages, files and users, send and draft messages, and work with canvases and lists, under admin approval, at the same rate limits as Slack's API. Teams chat messages are reachable through Microsoft's Work IQ MCP server, which reads them under the signed-in user's permissions, alongside the rest of Microsoft 365.

Where does Mojobase fit?

Mojobase is a third option for teams that want chat in the same place as the rest of the work, built for 1 to 25 people, and it works well for teams up to 100. Its Team chat keeps Slack's shape (channels, DMs and threads), sorts what's new into Needs you and Catch up, and treats AI agents as members you can @mention. It has no huddles or video calls, so teams that live on video are better served by Teams; Calendar adds the Meet or Zoom link to the event instead. It costs $39 a month for the first person and $25 for each after, with email, calendar, tasks, documents and the AI included.