# GPT-5.1-Codex vs GPT-5.4

> GPT-5.4 is the stronger model overall, scoring 59.4 to 38.6 on the Noometry Index. GPT-5.1-Codex costs 1.6× less per token, which makes it the better buy when GPT-5.4's lead doesn't matter for your workload.

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

## Summary

- They share 5 benchmarks with published results for both. GPT-5.1-Codex scores higher in 0 categories and GPT-5.4 in 3 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in math, where GPT-5.4 leads 73.5 to 30.3.
- The biggest single-benchmark swing is ProofBench: 9% for GPT-5.1-Codex and 56% for GPT-5.4.
- GPT-5.1-Codex is cheaper at $1.25 / $10 per million input/output tokens, against $2.50 / $15 for GPT-5.4.
- GPT-5.4 accepts more context: 1.05M tokens versus 400K.

## Snapshot

| | GPT-5.1-Codex | GPT-5.4 |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 38.6 | 59.4 |
| Rank | 186 | 16 |
| Context | 400K | 1.05M |
| Input $/M | $1.25 | $2.50 |
| Output $/M | $10 | $15 |
| Weights | Proprietary | Proprietary |

## Coding

- GPT-5.1-Codex: 41.9 (#116)
- GPT-5.4: 52.6 (#33)

| Benchmark | GPT-5.1-Codex | GPT-5.4 |
|---|---|---|
| LMArena WebDev | 1337 | 1465 |
| ALE-Bench | 1,245 | 1,607 |
| SWE-bench Verified | — | 76.9% |
| DeepSWE | — | 51.8% |
| SWE-bench Verified (bash only) | 66% | — |
| SciCode | — | 56.6% |
| GSO | — | 31.4% |
| WeirdML | — | 77.7% |
| LMArena Coding | — | 1497 |
| MirrorCode | — | 15.6% |
| AlgoTune | — | 1.85 |

## Agentic & Tool Use

- GPT-5.1-Codex: 38.0 (#33)
- GPT-5.4: 46.5 (#13)

| Benchmark | GPT-5.1-Codex | GPT-5.4 |
|---|---|---|
| Terminal-Bench | 60.4% | 81.8% |
| METR Time Horizons | 70.8% | 74.3% |
| APEX-Agents | — | 52.4% |
| τ²-bench Banking | — | 39.4% |
| DeepResearch Bench | — | 35.1% |
| PostTrainBench | — | 19% |
| GBAEval | — | 45.1% |
| LMArena Search | — | 1197 |
| Vending-Bench 2 | — | 6,144 |

## Reasoning

- GPT-5.1-Codex: —
- GPT-5.4: 61.8 (#19)

| Benchmark | GPT-5.1-Codex | GPT-5.4 |
|---|---|---|
| ARC-AGI-2 | — | 74% |
| Kagi LLM Benchmark | — | 63.8% |
| NYT Connections (extended) | — | 91.3% |
| ARC-AGI-1 | — | 93.7% |
| CritPt | — | 23.4% |
| Chess Puzzles | — | 44% |
| EnigmaEval | — | 16% |
| Thematic Generalization | — | 80% |
| EBR-Bench | — | 25.4% |
| LMArena Hard Prompts | — | 1485 |
| Mystery Game Puzzles | — | 37% |
| DTBench | — | 94.4% |
| LMCA | — | 52% |
| Epoch Capabilities Index | — | 156.81 |
| ForecastBench | — | 59.5 |

## Math

- GPT-5.1-Codex: 30.3 (#235)
- GPT-5.4: 73.5 (#19)

| Benchmark | GPT-5.1-Codex | GPT-5.4 |
|---|---|---|
| ProofBench | 9% | 56% |
| FrontierMath (Tiers 1-3) | — | 78.6% |
| FrontierMath Tier 4 | — | 49% |
| MathArena Final-Answer Competitions | — | 83.1% |
| OTIS Mock AIME 2024-2025 | — | 97.8% |
| LMArena Math | — | 1488 |
| FrontierMath (Feb 2025 set) | — | 47.6% |
| FrontierMath Tier 4 (v1) | — | 27.1% |

## Knowledge

- GPT-5.1-Codex: —
- GPT-5.4: 65.3 (#14)

| Benchmark | GPT-5.1-Codex | GPT-5.4 |
|---|---|---|
| GPQA Diamond | — | 93.3% |
| Humanity's Last Exam | — | 36.2% |
| SimpleQA Verified | — | 45.1% |
| Vectara Hallucination Rate | — | 7% |
| LMArena Expert | — | 1507 |

## Multimodal

- GPT-5.1-Codex: —
- GPT-5.4: 43.7 (#20)

| Benchmark | GPT-5.1-Codex | GPT-5.4 |
|---|---|---|
| LMArena Vision | — | 1303 |
| Blueprint-Bench 2 | — | 27.1% |
| Furniture Assembly | — | 37.5% |
| LMArena Document | — | 1471 |

## Multilingual

- GPT-5.1-Codex: —
- GPT-5.4: 56.2 (#23)

| Benchmark | GPT-5.1-Codex | GPT-5.4 |
|---|---|---|
| LMArena Non-English | — | 1465 |
| LMArena Chinese | — | 1519 |
| LMArena French | — | 1493 |
| LMArena German | — | 1472 |
| LMArena Japanese | — | 1485 |
| LMArena Korean | — | 1448 |
| LMArena Russian | — | 1480 |
| LMArena Spanish | — | 1454 |

## Instruction Following

- GPT-5.1-Codex: —
- GPT-5.4: 77.1 (#27)

| Benchmark | GPT-5.1-Codex | GPT-5.4 |
|---|---|---|
| LMArena Instruction Following | — | 1469 |

## Long Context

- GPT-5.1-Codex: —
- GPT-5.4: 50.3 (#8)

| Benchmark | GPT-5.1-Codex | GPT-5.4 |
|---|---|---|
| CL-bench | — | 27.9% |
| CL-bench Life | — | 21.7% |
| LMArena Longer Query | — | 1473 |

## Writing & Preference

- GPT-5.1-Codex: —
- GPT-5.4: 71.9 (#17)

| Benchmark | GPT-5.1-Codex | GPT-5.4 |
|---|---|---|
| LMArena Text | — | 1469 |
| LMArena Creative Writing | — | 1439 |
| EQ-Bench Creative Writing | — | 1840 |
| EQ-Bench 4 | — | 1272 |
| LMArena Multi-Turn | — | 1482 |

## FAQ

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

GPT-5.4 is the stronger model overall, scoring 59.4 to 38.6 on the Noometry Index. GPT-5.1-Codex costs 1.6× less per token, which makes it the better buy when GPT-5.4's lead doesn't matter for your workload.

### Which is cheaper, GPT-5.1-Codex or GPT-5.4?

GPT-5.1-Codex is cheaper. It lists at $1.25 per million input tokens and $10 per million output tokens; GPT-5.4 lists at $2.50 and $15.

### Is GPT-5.1-Codex or GPT-5.4 better for coding?

GPT-5.4 scores higher on coding benchmarks: 52.6 versus 41.9 in the Noometry coding category.

### Which has the bigger context window?

GPT-5.4 does, with 1.05M tokens against 400K.

### How many benchmarks do GPT-5.1-Codex and GPT-5.4 share?

5 benchmarks have published results for both models. GPT-5.1-Codex has 6 scored results on Noometry and GPT-5.4 has 68.