Model comparison
GPT-5.1-Codex vs GPT-5.4 Pro
GPT-5.4 Pro is the stronger model overall, scoring 58.8 to 38.2 on the Noometry Index. GPT-5.1-Codex costs 20× less per token, which makes it the better buy when GPT-5.4 Pro's lead doesn't matter for your workload.
Last verified . 0 shared benchmarks.
Summary
- The widest gap is in math, where GPT-5.4 Pro leads 72.0 to 29.3.
- GPT-5.1-Codex is cheaper at $1.25 / $10 per million input/output tokens, against $30 / $180 for GPT-5.4 Pro.
- GPT-5.4 Pro accepts more context: 1.05M tokens versus 400K.
Side by side
| GPT-5.1-Codex | GPT-5.4 Pro | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 38.2 | 58.8 |
| Released | 2025-11-12 | 2026-03-05 |
| Weights | Proprietary | Proprietary |
| Context window | 400K | 1.05M |
| Max output | 128K | 128K |
| Input $ / M tokens | $1.25 | $30 |
| Output $ / M tokens | $10 | $180 |
| Results tracked | 6 | 16 |
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Category by category
Coding Too close to call
GPT-5.1-Codex: 41.7 (#107), GPT-5.4 Pro: 42.6 (#89)
| Benchmark | GPT-5.1-Codex | GPT-5.4 Pro |
|---|---|---|
| SWE-bench Verified (bash only) | 66% | — |
| LMArena WebDev | 1337 | — |
| WeirdML | — | 57.4% |
| ALE-Bench | 1,245 | — |
Agentic & Tool Use Not comparable
GPT-5.1-Codex: 37.8 (#32), GPT-5.4 Pro: —
| Benchmark | GPT-5.1-Codex | GPT-5.4 Pro |
|---|---|---|
| Terminal-Bench | 60.4% | — |
| METR Time Horizons | 70.8% | — |
Reasoning Not comparable
GPT-5.1-Codex: —, GPT-5.4 Pro: 71.0 (#10)
| Benchmark | GPT-5.1-Codex | GPT-5.4 Pro |
|---|---|---|
| ARC-AGI-2 | — | 83.3% |
| SimpleBench | — | 74.1% |
| ARC-AGI-1 | — | 94.5% |
| CritPt | — | 30% |
| Chess Puzzles | — | 58.6% |
| EnigmaEval | — | 23.8% |
| Epoch Capabilities Index | — | 159.12 |
Math GPT-5.4 Pro leads
GPT-5.1-Codex: 29.3 (#218), GPT-5.4 Pro: 72.0 (#17)
| Benchmark | GPT-5.1-Codex | GPT-5.4 Pro |
|---|---|---|
| FrontierMath (Tiers 1-3) | — | 82.5% |
| FrontierMath Tier 4 | — | 58.5% |
| ProofBench | 9% | — |
| FrontierMath (Feb 2025 set) | — | 50% |
| FrontierMath Tier 4 (v1) | — | 37.5% |
Knowledge Not comparable
GPT-5.1-Codex: —, GPT-5.4 Pro: 68.3 (#6)
| Benchmark | GPT-5.1-Codex | GPT-5.4 Pro |
|---|---|---|
| GPQA Diamond | — | 94.6% |
| Humanity's Last Exam | — | 44.3% |
| SimpleQA Verified | — | 46.3% |
| Vectara Hallucination Rate | — | 8.3% |
Frequently asked questions
Is GPT-5.1-Codex better than GPT-5.4 Pro?
GPT-5.4 Pro is the stronger model overall, scoring 58.8 to 38.2 on the Noometry Index. GPT-5.1-Codex costs 20× less per token, which makes it the better buy when GPT-5.4 Pro's lead doesn't matter for your workload.
Which is cheaper, GPT-5.1-Codex or GPT-5.4 Pro?
GPT-5.1-Codex is cheaper. It lists at $1.25 per million input tokens and $10 per million output tokens; GPT-5.4 Pro lists at $30 and $180.
Is GPT-5.1-Codex or GPT-5.4 Pro better for coding?
They score almost the same on coding (41.7 vs 42.6); test both on your own repository before choosing.
Which has the bigger context window?
GPT-5.4 Pro does, with 1.05M tokens against 400K.
How many benchmarks do GPT-5.1-Codex and GPT-5.4 Pro share?
0 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and GPT-5.4 Pro has 16.