> GPT-5.1-Codex-Max is a closed AI model from OpenAI, released 19 Nov 2025. Index score 157 (GPT-4 = 100), rank 46 of 229 ranked models. API price $1.25 in / $10 out per million tokens, 400K context.

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# GPT-5.1-Codex-Max

OpenAI

Released 19 Nov 2025

Closed

Reasoning

Date verified

[Compare](https://themodelindex.org/compare/gpt-5-1-codex-max-vs-deepseek-v3-2/) [Announcement](https://openai.com/index/gpt-5-1-codex-max/)

157144–170

Index score

#46 · provisional, limited data

2/ 8

Core tests taken

2 of 6 areas · plus 0 anchor tests

−4

Versus the frontier at release

best then: Gemini 3 Pro

$1.25/ $10

Price per million tokens

input / output, list price

400K

Context window

tokens it reads at once

## Where it sits · on the frontier

_Chart: Model Index score of every scored model since late 2022, with the best closed and best open model over time_

Among the first models to reach this score.

## Test results · by area · tick = best by any model

Reasoning & knowledge

no evidence yet

GPQA Diamond

no result

Humanity's Last Exam

no result

Maths

no evidence yet

FrontierMath T1-3

no result

Coding

evidence

SWE-bench Verified

no result

Terminal-Bench

60%

Agents

no evidence yet

APEX-Agents

no result

Novel problems

no evidence yet

ARC-AGI-2

no result

Long tasks

evidence

METR time horizon

3.7 h

Independent results from the Epoch AI benchmarking hub, best reasoning setting. The core tests are shown here; anchor tests also inform the score and can be shown above.

## What others say · rank on each leaderboard

The Model Index

independent tests, our method

#46

of 219 · 157

Further left is better. Leaderboards measure different things: LMArena is people voting blind between two answers, the others are test scores. Click any row for the source.

## Best at · top three among current models

3rd

METR time horizon

Epoch AI · independent

Where this model places in the top three of today's models, on category leaderboards and on our core tests.

## Where to use it · prices checked 1 Oct 2026

#### From the lab

ChatGPT

app · subscription

↗

OpenAI API

API

↗

#### API providers · 1 · per million tokens, in / out

A

Azure

$1.25 / $10

cheapest

Provider prices come from OpenRouter's live listing; going direct to a provider can differ. Subscriptions are the lab's own apps.

## Facts and sources

Released

19 Nov 2025

Announcement

[openai.com ↗](https://openai.com/index/gpt-5-1-codex-max/)

Release entry

GPT-5.1-Codex-Max

Scored as

GPT-5.1-Codex-Max

Artificial Analysis index

–

Output speed

–

Hugging Face

closed weights

## OpenAI releases · around this one

GPT-5-Codex

Closed

15 SEP 2025

GPT-5.1

Closed

12 NOV 2025

index 153

GPT-5.1-Codex-Max

Closed

19 NOV 2025

index 157

GPT-5.2

Closed

11 DEC 2025

index 162

GPT-5.2-Codex

Closed

18 DEC 2025

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Source: https://themodelindex.org/models/gpt-5-1-codex-max/ · The Model Index · data as of 2026-10-01