API Rate Limit Calculator

What is API Rate Limit Calculator?

API rate limits cap the number of requests a client can make in a given time window — preventing abuse and protecting infrastructure. Knowing whether your expected traffic fits within a provider's rate limit — and by how much — lets you plan integrations confidently and set alert thresholds before users experience throttling errors (HTTP 429).

How to use this tool

1. 1 Enter your API's rate limit — for example, 1,000 requests per minute. This is the cap imposed by the API provider or your own gateway.
2. 2 Enter your expected traffic volume in the same or a different time unit. The calculator normalises both to requests-per-second for an accurate comparison.
3. 3 Read the usage percentage, headroom, and breach status from the result cards.
4. 4 Use the recommended alert thresholds at 80%, 85%, and 90% of the limit to configure monitoring alerts before the limit is hit.
5. 5 The normalised comparison table shows how the same rates compare across per-second, per-minute, per-hour, and per-day windows.

When would you use this?

• Before integrating a third-party API — verify your projected usage fits within the plan's rate limits before committing to a tier.
• Designing your own API gateway — use the threshold section to choose appropriate alert values for your monitoring system.
• Debugging intermittent 429 errors — verify whether your actual traffic volume is genuinely near or over the published limit.

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