Slack vs Teams is settled for most companies before the comparison starts: if you already pay for Microsoft 365, Teams is included and Slack is a second bill. That is the honest reason most organisations run Teams, and it is a good reason. Choose Slack anyway if messaging is where your work actually happens, if you collaborate constantly with people outside your company, or if your team lives in tools that integrate with Slack first. Choose Teams if you are a Microsoft shop, need large meetings, phone calling and compliance tooling, or want one identity and one admin console. Neither will fix a team that treats chat as an inbox.
Slack vs Teams: the seven axes that decide it
| Axis | Slack | Microsoft Teams |
|---|---|---|
| Real cost | A separate per seat subscription on top of whatever else you pay. | Included in most Microsoft 365 business and enterprise plans. Effectively already paid for. |
| Messaging quality | The product's whole purpose. Threads, search and channel organisation are cleaner. | Serviceable and much improved, but chat, channels and posts still confuse new users. |
| Meetings and calling | Huddles are excellent for quick ad hoc calls. Large formal meetings are not the strength. | Stronger: large meetings, webinars, recording, transcription, and a full phone system as an add-on. |
| Files | Files live in Slack or as links to your storage. Simple, and easy to lose track of. | Backed by SharePoint and OneDrive. Powerful, and the source of most permission confusion. |
| Working with outsiders | Shared channels with partner companies are a genuine differentiator, widely used by agencies and vendors. | Guest and external access work, but are more administrative and often restricted by IT policy. |
| Integrations | Deeper and broader for developer and startup tooling. Most SaaS products build a Slack app first. | Best-in-class for Microsoft products, and improving elsewhere. Power Platform connects it to internal workflows. |
| Admin and compliance | Retention, exports and eDiscovery on higher tiers. | Inherits the whole Microsoft compliance stack: retention policies, legal hold, data loss prevention, one identity system. |
Pricing is deliberately not quoted. Both vendors change plan structures and bundle contents, and the Teams comparison is meaningless without your existing Microsoft licence. Work out your incremental cost, not the list price.
When should you choose Slack?
- You work with outside companies daily. Agencies, consultancies, vendors and open source projects. A shared channel with a client is faster than email and does not require them to be guests in your directory.
- Your stack is not Microsoft. If you run Google Workspace, the Teams bundle argument disappears and the comparison becomes a fair fight, which Slack usually wins on messaging.
- Engineering and product teams are the core users. Deploy notifications, incident channels, alerting integrations: the ecosystem is deeper and better maintained on Slack.
- Search matters. If your team treats channels as a searchable record of decisions, Slack's search and threading make that record usable.
- You want people to enjoy it. That sounds soft. It is not. A communication tool people avoid is a communication tool that has failed.
Where Slack objectively loses: cost, meetings, and compliance depth. It is a real line item that finance will question every renewal, and if your organisation needs telephony and legal hold, you will end up buying Microsoft tools anyway and running two systems.
When should you choose Teams?
- You already pay for Microsoft 365. The incremental cost is close to zero. Buying Slack instead means justifying a new expense against a product you already own.
- Meetings are the centre of your culture. All-hands, client calls, training sessions, external webinars. Teams handles large and formal better.
- You need one identity and one admin console. Joiners and leavers, conditional access, device policy and data retention in one place is a real operational saving.
- Compliance is not optional. Regulated industries get retention, legal hold and data governance without adding a vendor.
- You want documents and conversation in one place. Co-authoring a document inside a channel, with the file living in SharePoint, is genuinely good once permissions are set up correctly.
Where Teams objectively loses: the mental model. New users cannot tell whether to use chat, a channel or a post, so important decisions end up in one-to-one messages nobody else can find. Notification behaviour is noisier by default, and the SharePoint layer beneath files creates permission problems that take an administrator to unpick.
What do people miss when comparing Slack vs Teams?
- Message history on free plans. Slack's free tier limits how far back you can see your own conversations. That is the single most effective upgrade prompt in software, and teams discover it about four months in, right when the history has become valuable. Assume you will pay.
- Migration is a culture change, not a data move. Exporting messages is possible. Getting three hundred people to change where they ask questions is the actual work, and it takes months of consistent enforcement, including closing the old tool on a fixed date.
- The permission model is the file model. In Teams, every channel has a SharePoint folder behind it, and private channels behave differently. Most "why can this person see that document" incidents trace back to not understanding this on day one.
- Neither replaces email safely by default. Without agreed norms, chat becomes a slower inbox with worse search and more anxiety. The rules that matter are boring and unglamorous: what belongs in a channel versus a direct message, when to use a thread, what response time is expected, and which channels are allowed to notify everyone.
- Check that your partners can join before you decide. Some client IT departments block one or the other outright. If half your external collaboration is impossible in the tool you picked, the feature comparison did not matter.
The part the tool will not do for you
Whichever you choose, the value comes from the operating rules around it: a channel naming convention, a decision about where decisions are recorded, an escalation path that is not "message the founder", and a meeting policy so the calling features do not simply generate more meetings.
That is design work, and it is what these two skills are for. Neither connects to Slack or Teams, and we do not sell a Slack skill or a Teams skill, so this is the honest adjacent recommendation rather than a matching product.
For the operating rules
$14.99
this skill
Writes the unglamorous documents that make a chat tool work: channel taxonomy, response time expectations, escalation paths, and a rollout plan with a date the old tool closes. Guide: the Owen skill walkthrough.
View Owen →For meeting and communication hygiene
$14.99
this skill
The communication layer above the tool: which updates are written rather than met about, how decisions get recorded and found later, and what leadership actually needs each week.
View Ryan →Frequently asked questions
Can a company run both Slack and Teams?
Plenty do, usually Teams for meetings and company-wide communication and Slack for a product or engineering group. It works, at the cost of people never being sure where to ask. If you do it, write down which tool owns which type of conversation and enforce it.
Is Teams free?
There is a free version with limits, but the version most businesses use arrives inside a Microsoft 365 subscription. If you already have that subscription, the honest answer is that Teams is already paid for.
Which is better for remote teams?
Slack, marginally, because asynchronous channel conversation is what it was built for and threads keep parallel discussions readable. Teams is better if your remote culture is meeting-heavy rather than writing-heavy.
Does switching lose our message history?
Exports exist on both sides, but imported history rarely lands in a usable, searchable form in the new tool. Most companies keep a read-only archive of the old system for a year and start fresh. Plan for that rather than promising a seamless move.
Do you sell a Slack or Teams skill?
Not currently. The catalogue covers roles rather than chat platforms, so the useful skills here are the operations and communication ones above. You can see the full role list in AI business skills for Claude, or browse business, consulting and operations skills. There are also 32 free skills if you want to try the format before paying.