Our goal is to make it effortless to pilot Windmill while ensuring costs scale predictably as adoption grows.
Seats & Pricing
| Seats | Price |
|---|---|
| First 25 seats | Free |
| Each additional seat | $10 USD per seat / month |
Why 25 free seats?
This lets HR teams, pilot groups, or early champions explore Windmill risk-free before rolling it out company-wide.How Billing Works
Monthly subscription
- We bill your default payment method once per month, at the end of the billing period. (via Stripe).
- The invoice total is based on the seat count being used at the end of the billing period.
Metered seat counting
- A seat is any active member account during the month.
- Inviting an employee to Windmill counts as a member, even if they haven’t logged in yet.
- Deactivated or deleted users no longer count toward your total.
Automatic sync
- Windmill regularly updates Stripe with your active seat count.
- If your usage changes, we adjust your subscription item quantity accordingly.
Proration Rules
Windmill follows industry-standard proration logic:| Scenario | What happens | Why |
|---|---|---|
| Seat count increases mid-cycle | We immediately add the extra seats and prorate the charge for the remaining days in the cycle. | You gain access right away and only pay for what you use. |
| Seat count decreases mid-cycle | We reduce the seat count for the next billing cycle (no mid-cycle refund). | Prevents invoice churn and keeps billing predictable. |
Example Invoices
| Date | Event | Seats Active | Charge |
|---|---|---|---|
| Jan 1 | Billing cycle starts | 25 | $0 (within free tier) |
| Jan 10 | Add 5 users | 30 | Prorated charge for 5 seats × 22 days |
| Feb 1 | Invoice | 30 | 5 paid seats × $10 = $50 |
| Feb 15 | Remove 8 users | 22 | No refund; seat count locked for Feb invoice |
| Mar 1 | Invoice | 22 | Back to $0 |
Frequently Asked Questions
Do I ever lose my free seats?
No. The first 25 active seats are always free, no matter how many total seats you have.What counts as an “active” seat?
Any user that can log in and use Windmill during the billing period.How do I estimate my bill?
- Count employees expected to be active.
- Subtract 25 free seats.
- Multiply the remainder by $10.
90 users → (90 − 25) × $10 = $650/month