# GPT-5.1-Codex vs GPT-5.4 nano

> GPT-5.4 nano is the stronger model overall, scoring 41.9 to 38.6 on the Noometry Index.

- Canonical page: https://noometry.com/compare/gpt-5-1-codex-vs-gpt-5-4-nano
- Last updated: 2026-10-12
- Shared benchmarks: 2

## 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 40.9 to 30.3.
- 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.

## Snapshot

| | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 38.6 | 41.9 |
| Rank | 186 | 125 |
| Context | 400K | 400K |
| Input $/M | $1.25 | $0.20 |
| Output $/M | $10 | $1.25 |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-5.1-Codex: 41.9 (#116)
- GPT-5.4 nano: 43.6 (#84)

| 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 | — | 1405 |

## Agentic & Tool Use

- GPT-5.1-Codex: 38.0 (#33)
- GPT-5.4 nano: —

| Benchmark | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| Terminal-Bench | 60.4% | — |
| METR Time Horizons | 70.8% | — |

## Reasoning

- GPT-5.1-Codex: —
- GPT-5.4 nano: 23.7 (#173)

| 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 | — | 1381 |
| Mystery Game Puzzles | — | 9% |
| DTBench | — | 80.3% |
| LMCA | — | 36.9% |
| Epoch Capabilities Index | — | 145.81 |
| ForecastBench | — | 57.3 |

## Math

- GPT-5.1-Codex: 30.3 (#235)
- GPT-5.4 nano: 40.9 (#88)

| 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

- GPT-5.1-Codex: —
- GPT-5.4 nano: 41.9 (#103)

| Benchmark | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| GPQA Diamond | — | 78.5% |
| SimpleQA Verified | — | 11.7% |
| Vectara Hallucination Rate | — | 3.1% |
| LMArena Expert | — | 1396 |

## Multimodal

- GPT-5.1-Codex: —
- GPT-5.4 nano: 36.7 (#78)

| Benchmark | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| LMArena Vision | — | 1196 |

## Multilingual

- GPT-5.1-Codex: —
- GPT-5.4 nano: 48.6 (#140)

| Benchmark | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| LMArena Non-English | — | 1359 |
| LMArena Chinese | — | 1392 |
| LMArena French | — | 1396 |
| LMArena German | — | 1367 |
| LMArena Japanese | — | 1343 |
| LMArena Korean | — | 1320 |
| LMArena Russian | — | 1363 |
| LMArena Spanish | — | 1371 |

## Instruction Following

- GPT-5.1-Codex: —
- GPT-5.4 nano: 71.9 (#144)

| Benchmark | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| LMArena Instruction Following | — | 1362 |

## Long Context

- GPT-5.1-Codex: —
- GPT-5.4 nano: 41.6 (#137)

| Benchmark | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| LMArena Longer Query | — | 1366 |

## Writing & Preference

- GPT-5.1-Codex: —
- GPT-5.4 nano: 55.7 (#142)

| Benchmark | GPT-5.1-Codex | GPT-5.4 nano |
|---|---|---|
| LMArena Text | — | 1372 |
| LMArena Creative Writing | — | 1314 |
| LMArena Multi-Turn | — | 1382 |

## FAQ

### Is GPT-5.1-Codex better than GPT-5.4 nano?

GPT-5.4 nano is the stronger model overall, scoring 41.9 to 38.6 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: 43.6 versus 41.9 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.