OpenAI: GPT-5.1-Codex-Max

OpenAI: GPT-5.1-Codex-Max is a large language model from OpenAI. It costs $1.25 per million input tokens and $10.00 per million output tokens. Its context window is 400K tokens.

ReasoningTool callingStructured outputPrompt cachingimage input

Input / 1M tokens: $1.25
Output / 1M tokens: $10.00
Cached input / 1M: $0.125
Context window: 400K

This model also charges $0.01 per search request

That is $10.00 per 1,000 requests, billed on top of the token prices above. On a typical 1,000-in / 500-out exchange the tokens cost $0.0063, so the search fee is 1.6× the token cost. Per-token rankings elsewhere ignore this entirely.

Who serves it cheapest

1 hosts serve GPT-5.1-Codex-Max. Same weights, same API - the price difference is pure margin and routing.

Providers serving OpenAI: GPT-5.1-Codex-Max, cheapest first
Provider	Input / 1M	Output / 1M	Context	Throughput	Uptime 24h
AzureCheapest	$1.25	$10.00	400K	-	100.0%

About GPT-5.1-Codex-Max

GPT-5.1-Codex-Max is OpenAI’s latest agentic coding model, designed for long-running, high-context software development tasks. It is based on an updated version of the 5.1 reasoning stack and trained on agentic...

Specifications

OpenAI: GPT-5.1-Codex-Max specifications
Model ID	`openai/gpt-5.1-codex-max`
Provider	OpenAI
Context window	400K tokens
Max output	128K tokens
Input modalities	text, image
Output modalities	text
Knowledge cutoff	-
Open weights	No
Released	December 4, 2025

Cheaper alternatives

Models that cost less than GPT-5.1-Codex-Max while keeping at least half its context window and every input modality it supports.

Gemini 3.5 Flash

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about the same cheaper

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Grok 4.6

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Grok 4.5

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Frequently asked

How much does OpenAI: GPT-5.1-Codex-Max cost?

$1.25 per million input tokens and $10.00 per million output tokens. Cached input reads cost $0.125 per million tokens.

What is the context window of OpenAI: GPT-5.1-Codex-Max?

400K tokens, with up to 128K tokens of output per request.

Does OpenAI: GPT-5.1-Codex-Max have extra fees beyond per-token pricing?

Yes. OpenAI: GPT-5.1-Codex-Max charges $0.01 per search request - $10.00 per 1,000 requests - on top of $1.25 per million input tokens and $10.00 per million output tokens. On a typical 1,000-input / 500-output exchange the search fee alone is 1.6× the token cost.

Confirm against the source: OpenAI official pricing.