OpenAI: GPT-6.1 Terra ProOfficial docs

OpenAI: GPT-6.1 Terra Pro

byOpenAI
Official docs

GPT-6.1 Terra Pro is a reasoning model from OpenAI released on Oct 26, 2026. It reads text, images and files and writes text, with a 1.05M token context window and up to 128K tokens per reply.

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It costs $1 per million input tokens and $5 per million output tokens. Cached input bills at $0.05, 95% less than fresh input.

It supports tool calling, structured JSON output and prompt caching.

2 providers serve it, including Kilo Gateway and NanoGPT.

Modalities
In / out price
$1 / $5 per 1M
Context
1.05M
Max output
128K
Released
Oct 26, 2026
Knowledge cutoff
n/a
  • Tool calling
  • Structured output
  • Reasoning
  • Prompt caching
  • Open weights
  • Free to use

GPT-6.1 Terra Pro pricing

USD, as listed on Oct 27, 2026. Most bills are input heavy, so the cached input rate matters as much as the headline price.

Input$1 / 1M tokens
Output$5 / 1M tokens
Cached input (read)$0.05 / 1M tokens
Cache write$1.25 / 1M tokens

GPT-6.1 Terra Pro providers

2 providers serve it, including Kilo Gateway and NanoGPT. Each host sets its own price and limits, so the cheapest one is not always the one with the longest context.

ProviderInput /MOutput /MCache read /MContextMax output
Kilo Gateway$1$5$0.051.05M128K
NanoGPT$1$5$0.051.05M128K

What GPT-6.1 Terra Pro costs per month

Pick a workload close to yours or type your own volumes.

GPT-6.1 Terra Pro per month
$84.75
Without caching
$128
Per request
$0.0028

Supported request parameters

What you can set when you call GPT-6.1 Terra Pro through an OpenAI compatible API.

  • Toolstools
  • Structured outputsstructured_outputs
  • Reasoningreasoning

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All OpenAI models

GPT-6.1 Terra Pro questions

How much does the GPT-6.1 Terra Pro API cost?

$1 per million input tokens and $5 per million output tokens, with cached input at $0.05. The estimator on this page turns that into a monthly bill for your own workload.

What is the context window of GPT-6.1 Terra Pro?

1,050,000 tokens of input, and it can write up to 128,000 tokens in one reply. As a rough guide, a million tokens is around 750,000 English words.

Which providers serve GPT-6.1 Terra Pro?

2 providers serve it, including Kilo Gateway and NanoGPT. Prices differ by host, so the Providers table on this page lists each one with its input and output price.

Does GPT-6.1 Terra Pro support tool calling?

Yes. It accepts tool definitions and can return JSON that matches a schema, which is what an agent needs to call your APIs.

Is GPT-6.1 Terra Pro open source?

No. OpenAI serves it through an API only, so you cannot download the weights or host it yourself.

When was GPT-6.1 Terra Pro released?

Oct 26, 2026.

Catalog data from models.dev (MIT licensed), refreshed daily, last on Oct 27, 2026. The summary is written from these facts.