GPT API Cost Calculator
Estimate OpenAI GPT API costs by token volume, request count, and model.
Pricing dataset updated Aug 28, 2026
Estimated monthly cost
$10.00
- Cost per request
- $0.0002
- Input tokens
- $3.00
- Output tokens
- $7.00
- Annualised
- $120.00
Estimates use public list pricing per 1M tokens. Batch, enterprise, and regional rates may differ.
How it works
OpenAI bills per million tokens, separately for input and output. Output tokens are usually several times more expensive than input tokens, so response length drives most of the bill.
Cached input tokens are charged at a large discount when the same prefix is resent. If your prompts share a long system message, caching is the single cheapest optimization available.
Worked example
Support assistant at 50,000 requests/month
With 1,200 input tokens and 350 output tokens per request on GPT-5 mini, monthly spend is roughly $15 for input and $35 for output - about $50/month before caching.