The honest answer to Slack vs Teams on cost is not about list prices side by side. It is about what you already pay for. Microsoft Teams is bundled into the Microsoft 365 plans most companies already hold, so its incremental cost is often close to zero. Slack is a separate subscription that lands on top. So when finance asks which is cheaper, the real question is whether Slack is adding enough value to justify a second bill for a capability the business already owns in Teams.
This page looks at the comparison the way a buyer side advisor would: net cost rather than sticker price, the overlap between the two tools, the switching costs of consolidating, and the narrow cases where keeping both still makes sense.
Slack vs Teams: the cost at a glance
Here is the picture most mid market buyers face. The figures below are list prices framed per user per month and are intended as orientation, not a quote.
| Item | Microsoft Teams | Slack |
|---|---|---|
| How it is sold | Bundled in Microsoft 365 Business and Enterprise suites | Standalone subscription per user |
| Entry paid tier | Included with the suite you already buy | Pro, around 8 US dollars per user per month on annual billing |
| Higher tier | Included through E3 and E5 suites | Business plus, higher per user, then Enterprise Grid custom |
| Typical net cost to add | Usually near zero if you hold Microsoft 365 | Full subscription on top of existing spend |
Source: Microsoft 365 and Slack public pricing pages, as of June 2026. List prices change often and exclude negotiated discounts; treat these as orientation and confirm against your own agreements.
The table makes the core point. Teams rarely appears as its own line item because it travels with the suite. Slack almost always appears as its own line item. That structural difference, not a few dollars of plan pricing, is what decides the comparison for most buyers. The same logic drives wider digital workplace cost optimization across overlapping tools.
Do I need Slack if I already have Microsoft Teams?
For the core need, which is internal chat plus meetings, the answer is usually no. Teams covers channels, direct messages, calls, and meetings, and it is already paid for inside Microsoft 365. Running Slack alongside it for the same purpose means paying twice for one capability. That is the textbook definition of duplicate spend, and it is one of the most common findings in a collaboration and video tool review.
Where Slack can still earn its place is in specific, documented cases: heavy reliance on third party integrations Slack does well, external partner or community workspaces, or a developer culture deeply built around Slack workflows. The test is whether a defined group depends on something Teams cannot match, not whether people simply prefer the Slack interface.
What does it cost to switch from Slack to Teams?
Consolidation is not free, and pretending otherwise undermines the case. The real switching costs are migration of active channels and history, retraining, rebuilding integrations and bots, and the temporary productivity dip while people adjust. These are genuine, but they are almost always one time costs measured in weeks, set against years of recurring Slack subscription fees that disappear once you consolidate.
A disciplined move plans the cutover around a renewal date so you stop paying for Slack the moment it is retired, not months later. This is the kind of sequencing covered in collaboration tool rationalization, where the timing of the cut is as important as the decision itself.
When is keeping both Slack and Teams justified?
There are real cases. A defined team that runs external customer or partner communities in Slack, a product organisation with deep Slack tooling, or a recent acquisition mid integration may all justify running both for a period. The discipline is to scope it: license Slack only for the group that needs it, not the whole company, and put a review date on it. Blanket Slack licensing across an organisation that already runs Teams is rarely defensible once the numbers are on the table.
How to decide for your organisation
Start by pulling active usage for both tools. If most of the company is active in Teams and only lightly active in Slack, the consolidation case is strong. If a specific group is heavily active in Slack for reasons Teams cannot cover, license that group and right size everyone else. Decisions should rest on usage data, not on which tool is louder internally.
The buyer side takeaway
On a net basis, Teams is almost always the cheaper option because it rides on a Microsoft 365 licence you already hold, while Slack is an additional subscription. That does not make Slack worthless, but it does mean the burden of proof sits with Slack to justify a second bill. For most mid market companies, consolidating onto Teams and licensing Slack only where it is genuinely needed is the move that holds savings without hurting how people work. To see the consolidation method end to end, read about collaboration tool rationalization and the wider digital workplace cost optimization approach.