o3 API cost calculator
o3 (OpenAI) is priced at $2 per million input tokens, $0.5 for cached input, and $8 per million output tokens — half that through the Batch API. Verified 2026-09-17 against OpenAI's pricing page.
What o3 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. | $0.0065 | $32.50 | $975 |
| RAG over documentsRetrieved context dominates — 12k in, 500 out, 30% cached. | $0.023 | $33.90 | $1,017 |
| Coding agentGrowing context every turn — 20k in, 1.5k out, 80% cached. | $0.028 | $84.00 | $2,520 |
| Batch classificationTiny prompts at volume through the Batch API — 800 in, 20 out. | $0.0009 | $176 | $5,280 |
Its blast radius when an agent loops
The coding-agent workload above at 30 requests a minute — $50.40 an hour — priced at each point a team usually finds out:
Hourly alert
$50.40
Next morning
$1,210
After a weekend
$3,024
Monthly invoice
$36,288