GPT-5 Medium vs GPT-5.1 Codex High: Specs & Benchmark Comparison
GPT-5 Medium and GPT-5.1 Codex High both come from OpenAI, GPT-5 Medium was released in August 2025, and GPT-5.1 Codex High followed 3 months later in November 2025.
We have 2 benchmark results for GPT-5 Medium and 1 benchmark result for GPT-5.1 Codex High, but they overlap on a single test: AIME 2025, where GPT-5.1 Codex High scores 97.0% against 89.0%.
On price the two are close: GPT-5 Medium costs $1.25 per million input tokens and $10 per million output tokens, GPT-5.1 Codex High $1.25 and $10. Both accept a context window of about 400K tokens. Both accept text and images as input.
| Characteristic | GPT-5 Medium | GPT-5.1 Codex High |
|---|---|---|
| Company | OpenAI | OpenAI |
| Release Date | August 6, 2025 | November 11, 2025 |
| Parameters | — | — |
| Multimodal | Yes | Yes |
| Context (input) | 400K | 400K |
| Context (output) | 128K | 128K |
| Input Price / 1M | $1.25 | $1.25 |
| Output Price / 1M | $10.00 | $10.00 |
| Average Score | 88.5% | 97.0% |
| Benchmarks | ||
| AIME 2025 | 89.0% | 97.0% |
Visual Benchmark Comparison
Verdict
GPT-5.1 Codex High leads in 1 out of 4 comparison categories.
Both models show comparable average scores: GPT-5 Medium — 0.9, GPT-5.1 Codex High — 1.0.
API cost is identical: input $1.25/1M, output $10.00/1M tokens.
Same context size: 400K tokens.
GPT-5.1 Codex High is newer: released 11/11/2025 vs 8/6/2025.
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Frequently Asked Questions
Which is better for coding — GPT-5 Medium or GPT-5.1 Codex High?
Which model is cheaper — GPT-5 Medium or GPT-5.1 Codex High?
Which has a larger context window — GPT-5 Medium or GPT-5.1 Codex High?
The GPT-5 Medium and GPT-5.1 Codex High comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the GPT-5 Medium or GPT-5.1 Codex High page. See also the complete list of AI model comparisons.