Model comparison
GPT-5.1-Codex vs GPT-5.4 nano
GPT-5.4 nano is the stronger model overall, scoring 41.9 to 38.2 on the Noometry Index.
Last verified . 2 shared benchmarks.
Summary
- They share 2 benchmarks with published results for both. GPT-5.1-Codex scores higher in 0 categories and GPT-5.4 nano in 2 categories; 2 gaps are clear of the uncertainty.
- The widest gap is in math, where GPT-5.4 nano leads 40.7 to 29.3.
- GPT-5.4 nano is cheaper at $0.20 / $1.25 per million input/output tokens, against $1.25 / $10 for GPT-5.1-Codex.
Side by side
| GPT-5.1-Codex | GPT-5.4 nano | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 38.2 | 41.9 |
| Released | 2025-11-12 | 2026-03-17 |
| Weights | Proprietary | Proprietary |
| Context window | 400K | 400K |
| Max output | 128K | 128K |
| Input $ / M tokens | $1.25 | $0.20 |
| Output $ / M tokens | $10 | $1.25 |
| Results tracked | 6 | 40 |
Sponsored placements are available on pages like this one. Advertise on Noometry
Category by category
Coding GPT-5.4 nano leads
GPT-5.1-Codex: 41.7 (#107), GPT-5.4 nano: 43.1 (#82)
| Benchmark | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| ALE-Bench | 1,245 | 1,005 |
| SWE-bench Verified (bash only) | 66% | — |
| LMArena WebDev | 1337 | — |
| SciCode | — | 46.9% |
| WeirdML | — | 49.2% |
| LMArena Coding | — | 1404 |
Agentic & Tool Use Not comparable
GPT-5.1-Codex: 37.8 (#32), GPT-5.4 nano: —
| Benchmark | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| Terminal-Bench | 60.4% | — |
| METR Time Horizons | 70.8% | — |
Reasoning Not comparable
GPT-5.1-Codex: —, GPT-5.4 nano: 23.8 (#159)
| Benchmark | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| ARC-AGI-2 | — | 5.7% |
| Kagi LLM Benchmark | — | 39.7% |
| ARC-AGI-1 | — | 51.5% |
| CritPt | — | 9.3% |
| Chess Puzzles | — | 30% |
| LMArena Hard Prompts | — | 1380 |
| Mystery Game Puzzles | — | 9% |
| DTBench | — | 80.3% |
| LMCA | — | 36.9% |
| Epoch Capabilities Index | — | 145.78 |
| ForecastBench | — | 57.3 |
Math GPT-5.4 nano leads
GPT-5.1-Codex: 29.3 (#218), GPT-5.4 nano: 40.7 (#76)
| Benchmark | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| ProofBench | 9% | 5% |
| FrontierMath (Tiers 1-3) | — | 44.9% |
| FrontierMath Tier 4 | — | 12.2% |
| OTIS Mock AIME 2024-2025 | — | 87.8% |
| LMArena Math | — | 1406 |
| FrontierMath (Feb 2025 set) | — | 25.9% |
| FrontierMath Tier 4 (v1) | — | 6.3% |
Knowledge Not comparable
GPT-5.1-Codex: —, GPT-5.4 nano: 41.8 (#94)
| Benchmark | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| GPQA Diamond | — | 78.5% |
| SimpleQA Verified | — | 11.7% |
| Vectara Hallucination Rate | — | 3.1% |
| LMArena Expert | — | 1397 |
Multimodal Not comparable
GPT-5.1-Codex: —, GPT-5.4 nano: 36.0 (#73)
| Benchmark | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| LMArena Vision | — | 1196 |
Multilingual Not comparable
GPT-5.1-Codex: —, GPT-5.4 nano: 48.8 (#136)
| Benchmark | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| LMArena Non-English | — | 1359 |
| LMArena Chinese | — | 1391 |
| LMArena French | — | 1396 |
| LMArena German | — | 1368 |
| LMArena Japanese | — | 1342 |
| LMArena Korean | — | 1321 |
| LMArena Russian | — | 1363 |
| LMArena Spanish | — | 1368 |
Instruction Following Not comparable
GPT-5.1-Codex: —, GPT-5.4 nano: 72.1 (#139)
| Benchmark | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| LMArena Instruction Following | — | 1362 |
Long Context Not comparable
GPT-5.1-Codex: —, GPT-5.4 nano: 41.6 (#131)
| Benchmark | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| LMArena Longer Query | — | 1365 |
Writing & Preference Not comparable
GPT-5.1-Codex: —, GPT-5.4 nano: 55.9 (#137)
| Benchmark | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| LMArena Text | — | 1372 |
| LMArena Creative Writing | — | 1313 |
| LMArena Multi-Turn | — | 1382 |
Frequently asked questions
Is GPT-5.1-Codex better than GPT-5.4 nano?
GPT-5.4 nano is the stronger model overall, scoring 41.9 to 38.2 on the Noometry Index.
Which is cheaper, GPT-5.1-Codex or GPT-5.4 nano?
GPT-5.4 nano is cheaper. It lists at $0.20 per million input tokens and $1.25 per million output tokens; GPT-5.1-Codex lists at $1.25 and $10.
Is GPT-5.1-Codex or GPT-5.4 nano better for coding?
GPT-5.4 nano scores higher on coding benchmarks: 43.1 versus 41.7 in the Noometry coding category.
Which has the bigger context window?
Both accept 400K tokens.
How many benchmarks do GPT-5.1-Codex and GPT-5.4 nano share?
2 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and GPT-5.4 nano has 40.