OpenAI: GPT-5.1-Codex

OpenAI: GPT-5.1-Codex 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: $0.130
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. Same weights, same API - the price difference is pure margin and routing.

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

About GPT-5.1-Codex

GPT-5.1-Codex is a specialized version of GPT-5.1 optimized for software engineering and coding workflows. It is designed for both interactive development sessions and long, independent execution of complex engineering tasks....

Specifications

OpenAI: GPT-5.1-Codex specifications
Model ID	`openai/gpt-5.1-codex`
Provider	OpenAI
Context window	400K tokens
Max output	128K tokens
Input modalities	text, image
Output modalities	text
Knowledge cutoff	-
Open weights	No
Released	November 13, 2025

Cheaper alternatives

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

Gemini 3.5 Flash

$1.50 in · $9.00 out

about the same cheaper

Fugu Max

$2.00 in · $6.00 out

1.1× cheaper

Qwen3.8 Max (0902)

$2.00 in · $6.00 out

1.1× cheaper

Grok 4.6

$2.00 in · $6.00 out

1.1× cheaper

Grok 4.5

$2.00 in · $6.00 out

1.1× cheaper

Frequently asked

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

$1.25 per million input tokens and $10.00 per million output tokens. Cached input reads cost $0.130 per million tokens.

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

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

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

Yes. OpenAI: GPT-5.1-Codex 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.