# Claude 3.5 Sonnet vs GPT-5.1-Codex

> GPT-5.1-Codex is the stronger model overall, scoring 38.2 to 34.4 on the Noometry Index.

- Canonical page: https://noometry.com/compare/claude-3-5-sonnet-vs-gpt-5-1-codex
- Last updated: 2026-10-10
- Shared benchmarks: 1

## Summary

- They share 1 benchmark with published results for both. Claude 3.5 Sonnet scores higher in 0 categories and GPT-5.1-Codex in 3 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in math, where GPT-5.1-Codex leads 29.3 to 18.0.

## Snapshot

| | Claude 3.5 Sonnet | GPT-5.1-Codex |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 34.4 | 38.2 |
| Rank | 225 | 178 |
| Context | — | 400K |
| Input $/M | — | $1.25 |
| Output $/M | — | $10 |
| Weights | Proprietary | Proprietary |

## Coding

- Claude 3.5 Sonnet: 39.5 (#145)
- GPT-5.1-Codex: 41.7 (#107)

| Benchmark | Claude 3.5 Sonnet | GPT-5.1-Codex |
|---|---|---|
| SWE-bench Verified (bash only) | — | 66% |
| Aider Polyglot | 51.6% | — |
| LMArena WebDev | — | 1337 |
| GSO | 4.6% | — |
| WeirdML | 40% | — |
| BigCodeBench Instruct | 46.8% | — |
| LiveBench Coding | 67.1% | — |
| LMArena Coding | 1343 | — |
| BigCodeBench Complete | 58.6% | — |
| CadEval | 48% | — |
| ALE-Bench | — | 1,245 |
| HumanEval+ | 81.7% | — |
| MBPP+ | 74.3% | — |

## Agentic & Tool Use

- Claude 3.5 Sonnet: 32.1 (#61)
- GPT-5.1-Codex: 37.8 (#32)

| Benchmark | Claude 3.5 Sonnet | GPT-5.1-Codex |
|---|---|---|
| METR Time Horizons | 45.2% | 70.8% |
| Terminal-Bench | — | 60.4% |
| TheAgentCompany | 24% | — |
| Cybench | 17.5% | — |
| BALROG | 32.6% | — |

## Reasoning

- Claude 3.5 Sonnet: 22.5 (#176)
- GPT-5.1-Codex: —

| Benchmark | Claude 3.5 Sonnet | GPT-5.1-Codex |
|---|---|---|
| SimpleBench | 41.4% | — |
| EnigmaEval | 0.9% | — |
| LiveBench Reasoning | 56.7% | — |
| LMArena Hard Prompts | 1305 | — |
| DTBench | 67.8% | — |
| LiveBench Data Analysis | 55% | — |
| Epoch Capabilities Index | 133.55 | — |
| ForecastBench | 60.7 | — |
| LiveBench | 59% | — |

## Math

- Claude 3.5 Sonnet: 18.0 (#282)
- GPT-5.1-Codex: 29.3 (#218)

| Benchmark | Claude 3.5 Sonnet | GPT-5.1-Codex |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 8.5% | — |
| ProofBench | — | 9% |
| Omni-MATH | 27.6% | — |
| LiveBench Math | 52.3% | — |
| LMArena Math | 1306 | — |
| MATH Level 5 | 56.9% | — |
| FrontierMath (Feb 2025 set) | 2.1% | — |
| FrontierMath Tier 4 (v1) | 0% | — |

## Knowledge

- Claude 3.5 Sonnet: 28.5 (#236)
- GPT-5.1-Codex: —

| Benchmark | Claude 3.5 Sonnet | GPT-5.1-Codex |
|---|---|---|
| GPQA Diamond | 55.3% | — |
| Humanity's Last Exam | 4.1% | — |
| MMLU-Pro | 77.7% | — |
| Confabulations | 19.9% | — |
| GPQA (HELM) | 56.5% | — |
| LMArena Expert | 1264 | — |
| MMLU | 87.3% | — |

## Multimodal

- Claude 3.5 Sonnet: 26.0 (#115)
- GPT-5.1-Codex: —

| Benchmark | Claude 3.5 Sonnet | GPT-5.1-Codex |
|---|---|---|
| LMArena Vision | 1125 | — |
| Video-MME | 60% | — |
| GeoBench | 62% | — |
| VPCT | 33% | — |

## Multilingual

- Claude 3.5 Sonnet: 43.4 (#180)
- GPT-5.1-Codex: —

| Benchmark | Claude 3.5 Sonnet | GPT-5.1-Codex |
|---|---|---|
| LMArena Non-English | 1283 | — |
| LMArena Chinese | 1271 | — |
| LMArena French | 1304 | — |
| LMArena German | 1297 | — |
| LMArena Japanese | 1234 | — |
| LMArena Korean | 1200 | — |
| LMArena Russian | 1305 | — |
| LMArena Spanish | 1289 | — |

## Instruction Following

- Claude 3.5 Sonnet: 69.0 (#177)
- GPT-5.1-Codex: —

| Benchmark | Claude 3.5 Sonnet | GPT-5.1-Codex |
|---|---|---|
| LiveBench Instruction Following | 69.3% | — |
| IFEval | 85.5% | — |
| LMArena Instruction Following | 1297 | — |

## Long Context

- Claude 3.5 Sonnet: 39.9 (#162)
- GPT-5.1-Codex: —

| Benchmark | Claude 3.5 Sonnet | GPT-5.1-Codex |
|---|---|---|
| LMArena Longer Query | 1311 | — |

## Writing & Preference

- Claude 3.5 Sonnet: 53.0 (#159)
- GPT-5.1-Codex: —

| Benchmark | Claude 3.5 Sonnet | GPT-5.1-Codex |
|---|---|---|
| LMArena Text | 1298 | — |
| LMArena Creative Writing | 1292 | — |
| Short-Story Creative Writing | 80.3% | — |
| EQ-Bench Creative Writing | 1451 | — |
| WildBench | 79.2% | — |
| LMArena Multi-Turn | 1326 | — |
| LiveBench Language | 53.8% | — |

## FAQ

### Is Claude 3.5 Sonnet better than GPT-5.1-Codex?

GPT-5.1-Codex is the stronger model overall, scoring 38.2 to 34.4 on the Noometry Index.

### Is Claude 3.5 Sonnet or GPT-5.1-Codex better for coding?

GPT-5.1-Codex scores higher on coding benchmarks: 41.7 versus 39.5 in the Noometry coding category.

### How many benchmarks do Claude 3.5 Sonnet and GPT-5.1-Codex share?

1 benchmark has published results for both models. Claude 3.5 Sonnet has 60 scored results on Noometry and GPT-5.1-Codex has 6.