GPT-5.6 Terra API cost calculator
GPT-5.6 Terra (OpenAI) is priced at $2 per million input tokens, $0.2 for cached input, and $12 per million output tokens — half that through the Batch API. Verified 2026-09-17 against OpenAI's pricing page.
What GPT-5.6 Terra 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. | $0.0076 | $37.80 | $1,134 |
| RAG over documentsRetrieved context dominates — 12k in, 500 out, 30% cached. | $0.024 | $35.28 | $1,058 |
| Coding agentGrowing context every turn — 20k in, 1.5k out, 80% cached. | $0.029 | $87.60 | $2,628 |
| Batch classificationTiny prompts at volume through the Batch API — 800 in, 20 out. | $0.0009 | $184 | $5,520 |
Its blast radius when an agent loops
The coding-agent workload above at 30 requests a minute — $52.56 an hour — priced at each point a team usually finds out:
Hourly alert
$52.56
Next morning
$1,261
After a weekend
$3,154
Monthly invoice
$37,843