What are the API rate limits for OpenAI and Anthropic?

Rate limits vary by tier. OpenAI: Tier 1 allows 500 RPM, Tier 5 allows 10,000 RPM. Anthropic: Free tier is 5 RPM, paid tiers go up to 4,000 RPM. Google Gemini: 15 RPM free, 1,000 RPM paid. Use the calculator above to check if your usage fits within limits.

How do I calculate if my API usage will hit rate limits?

Divide your concurrent users by average response time (in minutes) to get requests per minute. Compare against your provider's RPM limit. Example: 100 users with 5-second responses = ~1200 RPM, which needs Tier 3+ on OpenAI.

How can I avoid hitting API rate limits?

Implement request queuing, use exponential backoff for retries, cache common responses, batch non-urgent requests, and distribute load across providers. The rate limit calculator above helps you plan capacity.

AI API Rate Limit Calculator

Enter your expected traffic. See which providers can handle it — and what it'll cost.

Your Workload

Requests per Minute (RPM)

How many API calls your app makes per minute

Average Tokens per Request

Total tokens (input + output) per API call

Provider Tier

Your current spending tier (affects OpenAI/Anthropic limits)

Priority

What matters most to you?

Results

How to Handle Rate Limits

Request Queuing

Add a queue layer (BullMQ, AWS SQS) to buffer requests when you hit RPM limits. Smooths out traffic spikes without losing requests.

Multi-Key Rotation

Use multiple API keys and rotate between them. Effectively multiplies your RPM limit. Common pattern for high-throughput apps.

Model Routing

Route simple requests to high-RPM budget models (Gemini Flash: 4K RPM) and complex requests to flagships. Reduces load on expensive endpoints.

Batch API

For non-urgent workloads, use Batch APIs (OpenAI, Anthropic). They have separate, higher rate limits AND cost 50% less.

Exponential Backoff

When you get a 429 error, wait and retry with exponential backoff (1s, 2s, 4s, 8s). Most SDKs handle this automatically.

Response Caching

Cache identical or similar responses. Reduces API calls by 20-40% for chatbot workloads with repeated queries.

Calculate Your Full Monthly Cost

Rate limits are just one factor. See the complete picture — cost per request, monthly spend, and savings opportunities across all 59 models.

Try Cost Calculator →

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