ModelPricing.aiGPT-5.1 Codex Max API Pricing
GPT-5.1 Codex Max costs $1.25 per million input tokens and $10.00 per million output tokens on the OpenAI API. Prices are tracked from the official OpenAI pricing table and used by the ModelPricing.ai estimation API, so this page and the API always quote the same numbers. See all OpenAI model pricing or the full LLM pricing comparison.
GPT-5.1 Codex Max Pricing Per Million Tokens
| Tier | Input / 1M | Output / 1M | Cache read / 1M | Cache write / 1M |
|---|---|---|---|---|
| Standard | $1.25 | $10.00 | $0.125 | — |
What GPT-5.1 Codex Max Costs In Practice
Monthly cost at three representative workloads, using the standard text rate in effect today.
| Workload | Monthly cost |
|---|---|
| Light — 1M in / 200K out | $3.25 |
| Moderate — 10M in / 2M out | $32.50 |
| Heavy — 100M in / 20M out | $325.00 |
Need your own numbers? Use the LLM cost calculator or call the estimation API directly.
Compare GPT-5.1 Codex Max With Other Models
Looking for something cheaper from OpenAI? GPT-5 Nano is the lowest-priced option on input tokens.
GPT-5.1 Codex Max Pricing FAQ
How much does GPT-5.1 Codex Max cost per token?
GPT-5.1 Codex Max costs $1.25 per million input tokens and $10.00 per million output tokens on the OpenAI API. That works out to $0.0013 per thousand input tokens.
How much does it cost to run GPT-5.1 Codex Max per month?
At 1M in / 200K out per month, GPT-5.1 Codex Max costs about $3.25. A heavier workload of 100M input and 20M output tokens costs about $325.00.
Does GPT-5.1 Codex Max support prompt caching?
Yes. Cached input tokens are billed at $0.125 per million on GPT-5.1 Codex Max, compared with $1.25 per million for uncached input.
Estimate GPT-5.1 Codex Max costs programmatically
POST a token count to /v1/estimate with model gpt-5.1-codex-max and get a priced breakdown back, promotions
already applied.