GPT-5.1 Instant

by OpenAI

GPT-5.1 Instant is a model from OpenAI, released on November 12, 2025. It has a 400K-token context window and can generate up to 128K output tokens. API pricing is $1.25 per 1M input tokens and $10 per 1M output tokens. It ranks #55 of 220 models by Intelligence Score with a score of 36.7.

GPT-5.1 Instant is the next iteration of GPT-5, designed to be more conversational than earlier chat models. It features improved instruction following and an adaptive reasoning capability that lets it decide when to think before responding. GPT-5.1 Instant offers clearer and more engaging interactions, reducing jargon and enhancing user comprehension. It demonstrates significant improvements in coding tasks, making it a valuable tool for developers. GPT-5.1 Auto routes each query to the model best suited for it, so users typically don't need to choose a model manually.

Key specs

ProviderOpenAI
Release date2025-11-12
Licenseproprietary
Context window400K tokens
Max output128K tokens
Input price$1.25 / 1M tokens
Output price$10 / 1M tokens
Intelligence Score36.7
Coding index21.2
Output speed274 tokens/s
Time to first token2.59 s

Quick answers

What is the context window of GPT-5.1 Instant?

GPT-5.1 Instant has a context window of 400K tokens, with a maximum output of 128K tokens per response.

How much does GPT-5.1 Instant cost?

GPT-5.1 Instant costs $1.25 per 1M input tokens and $10 per 1M output tokens through the API.

Is GPT-5.1 Instant open source?

No. GPT-5.1 Instant is a proprietary model from OpenAI (proprietary license).

When was GPT-5.1 Instant released?

OpenAI released GPT-5.1 Instant on November 12, 2025.

How does GPT-5.1 Instant compare to Claude Opus 5.5 (Reasoning)?

GPT-5.1 Instant scores 36.7 on the Intelligence Score versus 60.5 for Claude Opus 5.5 (Reasoning), the current #1. Input pricing is $1.25 vs $4 per 1M tokens.

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