GPT-5 Pro API cost calculator
GPT-5 Pro (OpenAI) is priced at $15 per million input tokens, $15 for cached input, and $120 per million output tokens — half that through the Batch API. Verified 2026-09-17 against OpenAI's pricing page.
What GPT-5 Pro costs for common workloads
| Workload | Per request | Per day | Per month |
|---|---|---|---|
| Support chatbotShort turns with a reused system prompt — 3k in, 400 out, 60% cached. | $0.093 | $465 | $13,950 |
| RAG over documentsRetrieved context dominates — 12k in, 500 out, 30% cached. | $0.240 | $360 | $10,800 |
| Coding agentGrowing context every turn — 20k in, 1.5k out, 80% cached. | $0.480 | $1,440 | $43,200 |
| Batch classificationTiny prompts at volume through the Batch API — 800 in, 20 out. | $0.0072 | $1,440 | $43,200 |
Its blast radius when an agent loops
The coding-agent workload above at 30 requests a minute — $864 an hour — priced at each point a team usually finds out:
Hourly alert
$864
Next morning
$20,736
After a weekend
$51,840
Monthly invoice
$622,080