GPT-6.1 Terra vs GPT-5.6 Terra
Facts only. This page does not pick a winner. For a picked winner, see the use case comparison on Tools.
| GPT-6.1 Terra | GPT-5.6 Terra | |
|---|---|---|
| API model IDs | gpt-6.1-terra | gpt-5.6-terra |
| Context window | 1,050,000 | 1,050,000 |
| Lifecycle | active | active |
| License | proprietary | proprietary |
| Trains on API data | No | No |
| Zero data retention | on-request | on-request |
| Input per 1M tokens | $1 (verified 2026-11-05) | $2 (verified 2026-11-05) |
Frequently asked questions
- Which has the larger context window, GPT-6.1 Terra or GPT-5.6 Terra?
- GPT-6.1 Terra holds 1,050,000 tokens and GPT-5.6 Terra holds 1,050,000. Both hold 1,050,000 tokens. The context window counts the prompt, any attached files, and the reply together.
- Which is cheaper, GPT-6.1 Terra or GPT-5.6 Terra?
- Per million input tokens, GPT-6.1 Terra was $1 (verified 2026-11-05) and GPT-5.6 Terra was $2 (verified 2026-11-05). GPT-6.1 Terra is cheaper per input token. Output tokens cost $5 and $12 respectively, and output volume usually decides the bill.
- Does GPT-6.1 Terra or GPT-5.6 Terra train on API data?
- GPT-6.1 Terra does not train on API data by default, and GPT-5.6 Terra does not train on API data by default. Zero data retention is on-request for GPT-6.1 Terra and on-request for GPT-5.6 Terra. Verified 2026-09-08 and 2026-09-08 against the providers' own documentation.
- Is GPT-6.1 Terra or GPT-5.6 Terra being retired?
- GPT-6.1 Terra is active. GPT-5.6 Terra is active. Lifecycle checked 2026-11-05 and 2026-11-05. Pin a dated snapshot ID rather than an alias if a retirement would break you.