Nobody evaluates chat software by its annual cost, because at the moment of evaluation the team is eight people and the monthly figure is smaller than the coffee budget. The number that matters shows up two years later, when the team is forty and the invoice has quietly become a real line item.
This post is the multiplication nobody does up front. It deliberately avoids quoting specific Slack prices, because they change and a stale number is worse than none — check slack.com/pricing for the current figures and bring them here.
The formula
Chat pricing is per person, per month, with a discount for paying annually. So:
# the whole model, and it is not complicatedannual cost = seats × monthly price × 12# what people forget to include:# guests and contractors that count as seats# the tier upgrade you need for one specific feature# growth over the contract termFill in your plan's monthly price and multiply. Do it for today's headcount, then do it again for the headcount in your hiring plan. The second number is the one to actually budget against.
| Team size | Annual cost at $7/seat/mo | At $10 | At $15 |
|---|---|---|---|
| 10 people | $840 | $1,200 | $1,800 |
| 25 people | $2,100 | $3,000 | $4,500 |
| 50 people | $4,200 | $6,000 | $9,000 |
| 100 people | $8,400 | $12,000 | $18,000 |
| 250 people | $21,000 | $30,000 | $45,000 |
Those per-seat figures are illustrative placeholders, not Slack's prices — substitute your actual plan rate. The point of the table is the slope, not the digits.
The four costs people miss
1. The tier jump for one feature
You don't upgrade because you outgrew the plan. You upgrade because you need SSO, or a compliance export, or a specific admin control — and that one requirement re-prices every seat in the company, including the forty people who will never use the feature.
2. Guests and contractors
Depending on plan and guest type, external collaborators may consume seats. An agency relationship that adds six people to a shared channel is a pricing event, which is a strange sentence to have to write about a chat room.
3. Growth during the term
Annual plans are billed against a seat count that goes up when you hire. Budget against your hiring plan rather than today's org chart, or you'll be explaining a variance in Q3.
4. The history you're actually buying
Plenty of teams upgrade for one reason: the free plan's ~90-day history window. Worth naming explicitly, because if that's your reason, you're paying a permanent per-head subscription for access to text your team already wrote. That may still be worth it. It should be a conscious purchase.
What the alternative curve looks like
A self-hosted tool prices on infrastructure rather than people, which produces a fundamentally different shape: mostly flat, stepping up occasionally when you outgrow a box.
| Team size | Per-seat at $10/mo | Self-hosted Fluid Chat |
|---|---|---|
| 10 people | $1,200/yr | ~$100–180/yr of VPS |
| 25 people | $3,000/yr | ~$100–180/yr of VPS |
| 50 people | $6,000/yr | ~$400–800/yr |
| 100 people | $12,000/yr | ~$400–800/yr |
| 250 people | $30,000/yr | ~$1,200–3,000/yr |
Infrastructure figures are rough and provider-dependent — the shape is the argument, not the digits. Note the flat stretches: going from 25 people to 50 costs a per-seat plan twice as much and costs a server approximately nothing, because 50 people writing chat messages is not a demanding workload.
And the honest counterweight: self-hosting costs time, which is the expensive resource. Budget a few hours of setup and something like an hour a month of maintenance. At 10 people that time probably outweighs the savings. At 100 it very much doesn't.
The free-hosted third option
There's a case the table above misses, which is chat that's hosted for you and still $0. Fluid Chat's hosted version has no seat count, no history limit, and every admin feature included — so the 100-person row is $0 with no server to run.
The trade is scope rather than money: no huddles, voice or video, no SSO/SAML, no native mobile apps, no Slack Connect, and no Slack importer yet. If none of those are load-bearing for your team, the per-seat maths stops being a maths problem.
Run the multiplication, then try the $0 column.
Unlimited people, unlimited history, every feature, hosted or self-hosted. There's no card field to find.
A three-question decision
- 1What are you actually buying? If it's huddles, SSO or Slack Connect, pay — those are real products and nothing here replaces them.
- 2What's the number at your two-year headcount? Not today's. Multiply it out and look at it properly.
- 3Is history the only reason you'd upgrade? If yes, you have cheaper options, and at least one of them is free.