Model comparison
GPT-5.1-Codex vs GPT-5-Codex
- Input
- $1.25 / 1M tokens
- Output
- $10.00 / 1M tokens
- Context
- 400K
- Released
- 2025-11-19
- Input
- $1.25
- Output
- $10.00
- Context
- 400K
- Released
- 2025-09
GPT-5-Codex scores higher on 1 of the 1 benchmarks both models report; both charge the same $1.3 per 1M input tokens.
Specs and pricing side by side
| Spec | GPT-5.1-Codex | GPT-5-Codex |
|---|---|---|
| Maker | OpenAI | OpenAIsame |
| Released | 2025-11-19 | 2025-09 |
| Context window | 400K | 400Ksame |
| Max output | 128K | 128Ksame |
| Input price | $1.25 / 1M tokens | $1.25 |
| Output price | $10.00 / 1M tokens | $10.00 |
| Parameters | not published | Undisclosed |
| License | Proprietary (OpenAI API) | Proprietary |
| Weights | API only | API onlysame |
| Modalities | Text, Vision | Text, Visionsame |
| Knowledge cutoff | September 30, 2024 | Sep 2024 |
Benchmarks both models report
| Benchmark | GPT-5.1-Codex | GPT-5-Codex |
|---|---|---|
| SWE-bench Verified | 73.7% | 74.5% |
Scores are as published by each maker or its cited source; harness, reasoning effort and date can differ between rows, so treat small gaps as ties. Sources are listed on each model page.
Which one should you pick?
Pick GPT-5.1-Codex if…
- Your use case is: autonomous, multi-step coding tasks such as opening and iterating on pull requests.
Pick GPT-5-Codex if…
- You care about SWE-bench Verified (it scores higher on 1 shared benchmark).
- Your use case is: reach for it for long, independent execution of complex engineering tasks inside Codex (CLI, IDE, or cloud).
FAQ
Which is better, GPT-5.1-Codex or GPT-5-Codex?
GPT-5-Codex scores higher on 1 of the 1 benchmarks both models report; both charge the same $1.3 per 1M input tokens. The better pick depends on whether you value benchmark scores, price per token, context length or openness for your workload.
How do GPT-5.1-Codex and GPT-5-Codex pricing compare?
GPT-5.1-Codex: $1.25 / 1M tokens input, $10.00 / 1M tokens output. GPT-5-Codex: $1.25 input, $10.00 output (list API prices as published by each maker).
What are the context windows of GPT-5.1-Codex and GPT-5-Codex?
GPT-5.1-Codex offers 400K with up to 128K output; GPT-5-Codex offers 400K with up to 128K output.
Is GPT-5.1-Codex newer than GPT-5-Codex?
GPT-5.1-Codex was released 2025-11-19; GPT-5-Codex was released 2025-09.