API Rate Limit & Throttling Calculator
Calculate API rate limits, burst capacity, daily throughput capacity, and utilization percentage for API design and capacity planning.
Results
What is it?
For informational/educational purposes only. API rate limiting controls the number of requests a client can make in a given time period. Proper rate limit design prevents abuse, ensures fair use, and protects backend services from overload.
How to use
Enter your sustained rate limit (requests per minute), burst multiplier, expected daily request volume, and average response time. The calculator shows your rate per second, total daily capacity, utilization, and estimated concurrent connections (using Little's Law).
Example scenario
60 req/min rate limit, 2x burst = 2 req/s burst. Max daily capacity = 86,400 requests. If you expect 100,000 requests/day, utilization = 115.7%. You need to increase the rate limit or optimize request patterns.
Pro tip
Keep API utilization below 70-80% to handle traffic spikes gracefully. Implement exponential backoff with jitter in clients to avoid thundering herd problems when rate limits are hit. Token bucket and sliding window algorithms provide smoother rate limiting than fixed windows.