GPT-5.5 Pro API cost calculator
GPT-5.5 Pro (OpenAI) is priced at $30 per million input tokens, $30 for cached input, and $180 per million output tokens — half that through the Batch API. Verified 2026-09-17 against OpenAI's pricing page.
What GPT-5.5 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. | $0.162 | $810 | $24,300 |
| RAG over documentsRetrieved context dominates — 12k in, 500 out, 30% cached. | $0.450 | $675 | $20,250 |
| Coding agentGrowing context every turn — 20k in, 1.5k out, 80% cached. | $0.870 | $2,610 | $78,300 |
| Batch classificationTiny prompts at volume through the Batch API — 800 in, 20 out. | $0.014 | $2,760 | $82,800 |
Its blast radius when an agent loops
The coding-agent workload above at 30 requests a minute — $1,566 an hour — priced at each point a team usually finds out:
Hourly alert
$1,566
Next morning
$37,584
After a weekend
$93,960
Monthly invoice
$1,127,520