GPT-5.6 Terra API pricing
Official OpenAI list price, last checked Oct 29, 2026. Updated Oct 29, 2026.
GPT-5.6 Terra costs $2 per 1M input tokens and $12 per 1M output tokens, cached input at $0.20, per OpenAI's official pricing page (checked Oct 29, 2026). It's a premium-priced model: number 66 of 77 by blended price ($4.50 per 1M tokens at a 3 to 1 input to output mix). On LMArena's Text Arena it ranks #21 of 51 models we price (relative score 0 out of 100). Cheaper pick: Gemini 3.8 Flash scores 54 against 0 on the same board at $1.50 blended, 3.0x less. It's also one of our value picks for long documents.
GPT-5.6 Terra price per million tokens
| GPT-5.6 Terra price per million tokens | USD |
|---|---|
| Input | $2 |
| Cached input | $0.20 |
| Output | $12 |
| Blended, 3 parts input to 1 part output | $4.50 |
| Context window | Not listed |
Official note from OpenAI: Prompts up to 272K.
What GPT-5.6 Terra costs for real work
List-price estimates for a month, no discounts. Our math, not a quote: change the token counts in the plan vs API calculator.
| Workload | Tokens a month | GPT-5.6 Terra | Gemini 3.1 Pro Preview | Gemini 3.8 Flash |
|---|---|---|---|---|
| Light: a side project or personal assistant | 2M in, 0.5M out | $10.00 | $10.00 | $3.38 |
| Medium: a small team or one product feature | 20M in, 5M out | $100 | $100 | $33.75 |
| Heavy: a production app | 200M in, 50M out | $1,000 | $1,000 | $338 |
| Medium with 80% of input cached | 20M in (16M cached), 5M out | $71.20 | $71.20 | $22.95 |
How GPT-5.6 Terra ranks on LMArena
Relative score: 100 is the top model we price on that board. Rank is among the models in our price table, not the full leaderboard.
| Board | Rank | Score /100 |
|---|---|---|
| Chat (Text Arena) | #21 of 51 | 0 |
| Creative writing (Text Arena creative writing) | #28 of 51 | 0 |
| Roleplay and characters (Text Arena multi-turn) | #21 of 51 | 0 |
| Reasoning and math (Text Arena math) | #22 of 51 | 9 |
| Vision (Vision Arena) | #13 of 33 | 29 |
| Long documents (Document Arena) | #5 of 11 | 83 |
| Cheap bulk and agents (Agent Arena) | #24 of 34 | 41 |
Closest rivals to GPT-5.6 Terra
The models nearest in price, other makers first. Ranks are on Text Arena, where we have them.
| Model | In / out | Blended | Verdict |
|---|---|---|---|
| Gemini 3.1 Pro Preview | $2 / $12 | $4.50 | Gemini 3.1 Pro Preview wins: same price, higher score. Compare |
| Claude Sonnet 5.5 | $2 / $10 | $4 | Claude Sonnet 5.5 wins on both. Compare |
| Gemini 4 Argon | $2 / $10 | $4 | Gemini 4 Argon wins on both. Compare |
| Kimi K3.1 Pro | $2 / $10 | $4 | Kimi K3.1 Pro wins on price. Compare |
Cheaper alternatives to GPT-5.6 Terra
At least 40% cheaper blended, best LMArena score first.
| Model | In / out | Blended | Verdict |
|---|---|---|---|
| Gemini 3.8 Flash | $0.75 / $3.75 | $1.50 | Gemini 3.8 Flash wins on both. Compare |
| Muse Spark 1.3 | $1.25 / $4.25 | $2 | Muse Spark 1.3 wins on both. Compare |
| GLM-5.3 | $1.40 / $4.40 | $2.15 | GLM-5.3 wins on both. Compare |
More from OpenAI
- GPT-6.1 Sol$2 in, $10 out per 1M
- GPT-6 Sol$2 in, $10 out per 1M
- GPT-6.1 Terra$1 in, $5 out per 1M
- GPT-5.6 Sol$4 in, $20 out per 1M
- GPT-6 Luna$0.10 in, $0.50 out per 1M
FAQ
How much does the GPT-5.6 Terra API cost per million tokens?
$2 per 1M input tokens and $12 per 1M output tokens, plus $0.20 per 1M for cached input, as of Oct 29, 2026. A typical 3 to 1 input to output mix works out to $4.50 per 1M tokens.
Does GPT-5.6 Terra charge more for long prompts?
OpenAI doesn't list a long-prompt surcharge for GPT-5.6 Terra. Its pricing note says: Prompts up to 272K.
Is GPT-5.6 Terra cheaper than Gemini 3.1 Pro Preview?
About the same. A medium month (20M input and 5M output tokens) costs $100 on GPT-5.6 Terra and $100 on Gemini 3.1 Pro Preview at list price. On Text Arena, GPT-5.6 Terra ranks #21 and Gemini 3.1 Pro Preview #9.
How does GPT-5.6 Terra rank on LMArena?
On Text Arena it is #21 of 51 models we price, with a relative score of 0 out of 100. It ranks on 7 of 8 boards we track.
What is a cheaper alternative to GPT-5.6 Terra?
Gemini 3.8 Flash costs $0.75 in and $3.75 out per 1M tokens, about 3.0x less blended, and scores 54 on Text Arena against 0 for GPT-5.6 Terra.
Where does this GPT-5.6 Terra price come from?
From OpenAI's official pricing page, which we check every day. This page was last checked Oct 29, 2026.