Slack and Microsoft Teams both give a team chat channels, direct messages and calls. Slack is a messaging tool built to connect with your other apps. Teams is chat and meetings that come with Microsoft 365. For a small business, what you already pay for often decides it.
The short verdict
Pick Slack if you use Google Workspace or many separate apps, your team lives in chat all day, and you want channels with clients or partners.
Pick Teams if you already pay for Microsoft 365, or you want chat, video meetings, email and Office apps under one bill.
If you are a team of two or three, a shared email inbox and a group chat may be enough for now.
Prices and plans
All facts below come from each vendor's own pages, in US dollars, as of October 2026.
- Free: messages saved and searchable for 90 days, up to 10 apps, one-to-one huddles only, and one-to-one messages with people outside your company.
- Pro: $7.25 per user a month billed annually, or $8.75 billed monthly. Group huddles, unlimited message history, and channels with up to 250 outside organizations.
- Business+: $15 per user a month billed annually, or $18 billed monthly. Adds more advanced AI features.
- Enterprise+: $45 per user a month, annual billing only, through sales.
At the time of writing, Slack offered 50% off the first 3 months on monthly Pro and Business+ plans, for teams that buy within 7 days of creating their workspace.
- Teams Essentials: $4 per user a month, paid yearly. Chat, calls and video meetings up to 30 hours with up to 300 people, recordings with transcripts, and 10GB of cloud storage per user.
- Microsoft 365 Business Basic: $7 per user a month, paid yearly. Teams plus business email, web and mobile Office apps, and 1TB of cloud storage per user.
- Microsoft 365 Business Standard with Copilot: $23.50 per user a month, paid yearly. Adds desktop Office apps and Copilot in the apps.
Microsoft also sells Microsoft 365 plans without Teams, so check that the plan you pick says it includes Teams. The free version of Teams is meant for personal use, with meetings up to 60 minutes.
The differences that matter
What you already pay for
If your business email runs on Microsoft 365, Teams may already be in your plan. Adding Slack means a second bill for a similar job. If you use Google Workspace, Teams would be an extra tool, and Slack fits in more naturally. See Google Workspace vs Microsoft 365 if you have not picked yet.
The free plan
Slack's free plan is a real way to start, but messages older than 90 days are no longer saved and searchable. For a business, old decisions and client details live in those messages. Plan to pay, or keep key decisions somewhere else. The free Teams is aimed at personal use, so a business will usually start on Teams Essentials or a Microsoft 365 plan.
Meetings
Teams was built with meetings at its center. Teams Essentials includes meetings up to 30 hours with up to 300 people, plus recordings and transcripts. Slack's huddles are calls you start from inside Slack. On the free plan they are one-to-one only, and Slack's Pro page lists video calls and screen sharing with up to 50 teammates. If you run client video calls, Teams covers that in the same plan. With Slack, you may still want a separate tool such as Zoom or Google Meet.
Working with people outside your company
Slack Connect lets you share channels with other companies. Pro allows up to 250 outside organizations. This is useful for agencies and contractors who talk to clients every day. Teams supports guest access on its Microsoft 365 plans.
Price for a small team
For five people on annual billing, list prices are:
- Teams Essentials: $20 a month.
- Microsoft 365 Business Basic, with email and Office web apps: $35 a month.
- Slack Pro: $36.25 a month, before any email or office suite.
How to decide
- Check what your email runs on. Microsoft points to Teams. Google points to Slack.
- Count how many client calls you run each week.
- Decide if you need shared channels with clients or partners.
- Try the free Slack plan or a Microsoft trial with your real team for two weeks.
Chat is fast, but it is a poor place to keep how things are done. Put repeated work in an SOP, and decisions in meeting notes. For more on working apart, see how to manage a remote team.