GPT-5 nano API cost calculator
GPT-5 nano (OpenAI) is priced at $0.05 per million input tokens, $0.005 for cached input, and $0.4 per million output tokens — half that through the Batch API. Verified 2026-09-17 against OpenAI's pricing page.
What GPT-5 nano 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. | $0.0002 | $1.15 | $34.35 |
| RAG over documentsRetrieved context dominates — 12k in, 500 out, 30% cached. | $0.0006 | $0.957 | $28.71 |
| Coding agentGrowing context every turn — 20k in, 1.5k out, 80% cached. | $0.0009 | $2.64 | $79.20 |
| Batch classificationTiny prompts at volume through the Batch API — 800 in, 20 out. | $0.0000 | $4.80 | $144 |
Its blast radius when an agent loops
The coding-agent workload above at 30 requests a minute — $1.58 an hour — priced at each point a team usually finds out:
Hourly alert
$1.58
Next morning
$38.02
After a weekend
$95.04
Monthly invoice
$1,140