What free-tier and trial users cost you in API spend — and per paying customer.
Trials burn tokens whether or not they convert, so track cost per acquired customer, not just total spend. Size the paid-side margin on the AI SaaS margin calculator and per-user cost on the cost per active user calculator.
Free AI trial-burn calculator — trial signups, tokens each and conversion rate to your monthly free-user API cost and cost per paying customer.
Multiply trial signups by the tokens each consumes by your per-token price. Then divide the total by how many convert to paying to get your true API cost per acquired customer — the number that tells you whether the free tier pays for itself.
Cap tokens or requests per trial user, require a card or email verification, rate-limit aggressively, and use a cheaper model for free tier than for paid. Freemium AI products routinely find that a small fraction of free users drive most of the burn.
Cost at different volumes:
| Volume | Monthly | Yearly |
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