One agent session
1M input tokens and 100K output tokens, no caching.
- Input1M x $2 = $2.00
- Output0.1M x $12 = $1.20
$3.20per session
OpenAI - Closed weights
GPT-5.6 Terra pricing and specs
GPT-5.6 Terra is a closed-weights model from OpenAI that costs $2 per 1M input tokens and $12 per 1M output tokens on the first-party API, with a 1.05M-token context window.
Last verified from developers.openai.com. All sources
- Input / 1M
- $2
- Output / 1M
- $12
- Context
- 1.05M tokens
- Weights
- Closed
Pricing per 1M tokens
| Item | Price / 1M tokens |
|---|---|
| InputPrompts up to 272,000 tokens | $2 |
| OutputPrompts up to 272,000 tokens | $12 |
| Cache readPrompts up to 272,000 tokens | $0.20 |
| Cache write (5 minutes)Prompts up to 272,000 tokens | $2.50 |
| Batch inputBatch requests, prompts up to 272,000 tokens | $1 |
| Batch outputBatch requests, prompts up to 272,000 tokens | $6 |
| Long-context inputPrompts over 272,000 tokens | $4 |
| Long-context outputPrompts over 272,000 tokens | $18 |
| Long-context cache readPrompts over 272,000 tokens | $0.40 |
| Long-context cache write (5 minutes)Prompts over 272,000 tokens | $5 |
| Long-context batch inputBatch requests, prompts over 272,000 tokens | $2 |
| Long-context batch outputBatch requests, prompts over 272,000 tokens | $9 |
| Fast mode inputFast mode requests | $4 |
| Fast mode outputFast mode requests | $24 |
Note: Priced by prompt length: a request with more than 272K input tokens pays the long-context pricing rates for the whole request (short context is <=272K input tokens). OpenAI's cache write (1.25x uncached input) is recorded in cache write; OpenAI does not sell a separate 1-hour write. Batch and Flex are both 50% of Standard. Fast mode is 2x Standard. Maximum input tokens 922,000.
Specs
- Context window
- 1,050,000 tokens
- Max output
- 128,000 tokens
- Release date
- Provider
- OpenAI
- API model id
gpt-5.6-terra- Vercel AI Gateway id
openai/gpt-5.6-terra- Weights
- Closed weights
What GPT-5.6 Terra costs in practice
Worked from the standard list rates above, with the math shown so you can swap in your own token counts. These use the base rates, which apply while each request's prompt stays at or under 272,000 tokens; above that, GPT-5.6 Terra bills $4 input and $18 output for the whole request.
A chat app
10,000 requests a day at 2K input and 500 output tokens each.
- Input20M x $2 = $40.00
- Output5M x $12 = $60.00
$100.00per day
$3,000.00 per 30-day month
The same session at a 90% cache hit
90% of the input is read from the prompt cache. The one-time cache write premium is not included.
- Cached input0.9M x $0.20 = $0.18
- Uncached input0.1M x $2 = $0.20
- Output0.1M x $12 = $1.20
$1.58per session
Compare with
| Model | Input / 1M | Output / 1M |
|---|---|---|
| GPT-5.6 Terra (this page) | $2 | $12 |
| Gemini 3.1 Pro PreviewGoogle | $2 | $12 |
| Amazon Nova PremierAmazon | $2.50 | $12.50 |
| Claude Sonnet 5Anthropic | $2 | $10 |
| Claude Sonnet 5.5Anthropic | $2 | $10 |
| GPT-4oOpenAI | $2.50 | $10 |
| GPT-5OpenAI | $1.25 | $10 |
| GPT-5.1OpenAI | $1.25 | $10 |
| GPT-5.2OpenAI | $1.75 | $14 |
| GPT-5.3-CodexOpenAI | $1.75 | $14 |
| GPT-6 SolOpenAI | $2 | $10 |
Related reading
- Codex CLI 0.163: Instant Steering Is Now the DefaultCodex CLI 0.163.0 makes mid-response steering the default and adds searchable /config and a leader key. What changed and what to check before upgrading.
- Tool Calling Under the Hood: Claude Messages vs OpenAI ResponsesHow tool calling works on the wire: JSON schema tools, parallel calls, tool_choice, strict mode and streaming deltas in Claude Messages vs OpenAI Responses.
- Codex 'gpt-5.5 Model Is Not Supported' Error: The FixCodex says gpt-5.5 is not supported with a ChatGPT account because OpenAI retired it from ChatGPT sign-in on October 14. The fix and what still works.
- Codex CLI Background Daemon: How to Turn It OffCodex CLI starts a persistent, self-updating background daemon since 0.157.0. What it does, why it hit Hacker News and the reported workaround to turn it off.
- Codex CLI 0.162: Managed Worktrees and Pinned TasksCodex CLI 0.162 lets the agent create and list its own Git worktrees, adds pinned tasks and custom provider capability overrides. What to change this week.
- ChatGPT Free vs Go vs Plus After GPT-6: Which Model You GetFree and Go ($8) both get GPT-6 Luna in Chat. Plus ($20) is the cheapest plan with GPT-6 Sol and full Codex. What each ChatGPT plan buys now.
FAQ
How much does GPT-5.6 Terra cost per million tokens?
GPT-5.6 Terra costs $2 per 1M input tokens and $12 per 1M output tokens on OpenAI's first-party API, per developers.openai.com on October 17, 2026. Per 1M tokens, cache reads cost $0.20, and the batch rate is $1 input and $6 output. Prompts over 272,000 tokens are billed at $4 input and $18 output for the whole request.
What is GPT-5.6 Terra's context window?
GPT-5.6 Terra has a 1,050,000-token context window and returns up to 128,000 output tokens per response.
Are GPT-5.6 Terra's weights open?
No. GPT-5.6 Terra is a closed-weights model. You call it through OpenAI's API as gpt-5.6-terra or through Vercel AI Gateway as openai/gpt-5.6-terra.
When was GPT-5.6 Terra released?
OpenAI released GPT-5.6 Terra on July 9, 2026.
Sources
Last verified from developers.openai.com.
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