OpenAI

GPT-5.1 Codex Max

A version of GPT-5.1 Codex optimized for long-running coding tasks.

ActiveAvailable from 2 providers
Tool callingCan invoke external tools and APIs (function calling) mid-response.Structured outputCan return JSON or schema-constrained responses instead of free text.ReasoningUses extended thinking / chain-of-thought for harder multi-step problems.Effort controlLets you dial thinking depth (low / medium / high) to trade cost for quality.Fine-tuningSupports training a custom variant on your own data.

Source: OpenAI models, OpenAI pricing

Price per 1M tokens
$1.25 in / $10 out
Context window400,000
Max output128,000
Cache read$0.125 / M
Batch discount-50%
ModalitiesText, Image → Text
Priced across2 providers

Pricing

Every billing leg from the live catalog, in USD per 1M tokens.

Billing legRateBatch
Input$1.25 / M$0.625 / M
Output$10 / M$5 / M
Cache read$0.125 / M$0.0625 / M

Cost calculator

Billing-grade math over the rate card above, including the thinking tokens most estimates miss.

Hidden reasoning tokens bill as output. 1.0x = thinking off. Medium-effort reasoning typically lands near 3x; heavy reasoning runs 6x to 8x. Set it to match your workload.

Estimated monthly cost
$850
at current list prices
Fresh input$250
Cached input$0.00
Output incl. thinking$600
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Compare providers

The same model, priced across every platform that serves it. Lowest combined in/out rate is flagged.

PlatformInput / MOutput / MCache read / MBatchAccess
OpenAILowest
$1.25$10$0.125✓First-party API
Cursor
$1.25$10$0.125—Direct

Price history

Has this model gotten cheaper or more expensive?

No changePriced at $1.25 / $10 per 1M since May 30, 2026.

More from OpenAI

Other models from the same provider.

GPT-5.6 Sol
openai/gpt-5.6-sol
$5 / $30 in / out per 1M
GPT-5.6 Terra
openai/gpt-5.6-terra
$2.5 / $15 in / out per 1M
GPT-5.6 Luna
openai/gpt-5.6-luna
$1 / $6 in / out per 1M
GPT-5.5
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$5 / $30 in / out per 1M
GPT-5.5 Pro
openai/gpt-5.5-pro
$30 / $180 in / out per 1M
GPT-5.4
openai/gpt-5.4
$2.5 / $15 in / out per 1M

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Rates are generated from SuperPenguin's live pricing catalog.