API Request Cost Calculator

API request cost calculator

✓ Last verified: 2026-07-15· Source: official provider pricing page· Auto-monitored — report change →

The headline "price per call" is only half the bill. Enter your volume, per-request price and average response size to get the true monthly cost — request fees plus data egress — with cost per 1,000 calls and a yearly projection.

The per-call price hides the bandwidth

Almost every API quotes a tidy price per request — say $0.50 per 1,000 calls. What it doesn't quote is the cost of sending the response bytes to your users. A 30 KB JSON response served a million times is ~30 GB of egress, and at a typical $0.09/GB that's an extra line on your cloud bill the API price never showed. For lean responses it's negligible; for image, file or large-payload APIs, egress can match or beat the request fees. This calculator adds both so the "true cost per call" is honest.

Count the invisible traffic

Volume estimates are usually too low because they only count user-facing calls. Webhooks, callbacks, polling loops and automatic retries are all real requests — they burn rate limit and often get billed even though no human sees them. A poll-every-5-seconds integration is 17,000 calls a day per client before anyone clicks anything. When you size an API, pad for background traffic, or you'll be surprised on the invoice.

Lower the bill

Two levers dominate: fewer, fatter calls (batch endpoints, GraphQL field selection, caching responses) cut request fees, and smaller responses (gzip/brotli, pagination, trimming fields, modern image formats) cut egress. Serving from a zero-egress store removes the bandwidth line entirely — model that with the cloud egress cost calculator. For the whole picture across services, use the API stack cost calculator, and read the API costs that double your bill.

Related tools & guides

Cloud egress cost calculator · API stack cost calculator · API alternatives finder · free API tiers

Frequently asked questions

How do I calculate the cost of an API per request?

Take the provider's price per request (or per 1,000 calls), multiply by your monthly request volume, then add the data egress: average response size × number of requests, priced per GB. The total divided by your call count gives a true cost per request that includes bandwidth — which the headline price usually hides.

Why include egress in API cost?

Many APIs advertise a per-call price but you also pay your cloud provider to send the response bytes to users. A 50 KB response served a million times is 50 GB of egress — at ~$0.09/GB that's an extra $4.50 the per-call price never mentioned. For data-heavy or high-volume APIs, egress can rival the request fees.

Do webhooks and retries count as requests?

Yes. Webhooks, callbacks, polling and automatic retries are all real requests that consume rate limit and may be billed, even though a human never sees them. When you estimate volume, include background traffic — it's a common reason a bill comes in higher than expected.