# Claude 3 Opus vs GPT-5-Codex

> GPT-5-Codex is the stronger model overall, scoring 37.9 to 29.5 on the Noometry Index.

- Canonical page: https://noometry.com/compare/claude-3-opus-vs-gpt-5-codex
- Last updated: 2026-10-11
- Shared benchmarks: 1

## Summary

- They share 1 benchmark with published results for both. Claude 3 Opus scores higher in 0 categories and GPT-5-Codex in 3 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where GPT-5-Codex leads 30.9 to 14.6.
- The biggest single-benchmark swing is WeirdML: 19.2% for Claude 3 Opus and 54.5% for GPT-5-Codex.

## Snapshot

| | Claude 3 Opus | GPT-5-Codex |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 29.5 | 37.9 |
| Rank | 310 | 192 |
| Context | — | 400K |
| Input $/M | — | $1.25 |
| Output $/M | — | $10 |
| Weights | Proprietary | Proprietary |

## Coding

- Claude 3 Opus: 32.9 (#267)
- GPT-5-Codex: 42.4 (#103)

| Benchmark | Claude 3 Opus | GPT-5-Codex |
|---|---|---|
| WeirdML | 19.2% | 54.5% |
| BigCodeBench Instruct | 45.5% | — |
| LiveBench Coding | 38.6% | — |
| LMArena Coding | 1264 | — |
| BigCodeBench Complete | 57.4% | — |
| HumanEval+ | 77.4% | — |
| MBPP+ | 73.3% | — |

## Agentic & Tool Use

- Claude 3 Opus: 24.6 (#116)
- GPT-5-Codex: 31.0 (#72)

| Benchmark | Claude 3 Opus | GPT-5-Codex |
|---|---|---|
| Terminal-Bench | — | 44.3% |
| Cybench | 10% | — |
| METR Time Horizons | 29.5% | — |

## Reasoning

- Claude 3 Opus: 14.6 (#324)
- GPT-5-Codex: 30.9 (#83)

| Benchmark | Claude 3 Opus | GPT-5-Codex |
|---|---|---|
| SimpleBench | 23.5% | — |
| Kagi LLM Benchmark | — | 70.3% |
| Chess Puzzles | 5% | — |
| EnigmaEval | 0.8% | — |
| LiveBench Reasoning | 40.6% | — |
| LMArena Hard Prompts | 1245 | — |
| DTBench | 61.6% | — |
| LiveBench Data Analysis | 57.9% | — |
| LMCA | 17% | — |
| Epoch Capabilities Index | 126.91 | — |
| ForecastBench | 58.4 | — |
| LiveBench | 49.2% | — |
| WinoGrande | 88.5% | — |

## Math

- Claude 3 Opus: 14.8 (#299)
- GPT-5-Codex: —

| Benchmark | Claude 3 Opus | GPT-5-Codex |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 4.7% | — |
| LiveBench Math | 43.6% | — |
| LMArena Math | 1273 | — |
| MATH Level 5 | 37.5% | — |

## Knowledge

- Claude 3 Opus: 24.5 (#267)
- GPT-5-Codex: —

| Benchmark | Claude 3 Opus | GPT-5-Codex |
|---|---|---|
| GPQA Diamond | 47.2% | — |
| SimpleQA Verified | 12.6% | — |
| Confabulations | 22.7% | — |
| LMArena Expert | 1223 | — |
| MMLU | 84.6% | — |

## Multimodal

- Claude 3 Opus: 27.1 (#116)
- GPT-5-Codex: —

| Benchmark | Claude 3 Opus | GPT-5-Codex |
|---|---|---|
| LMArena Vision | 1023 | — |

## Multilingual

- Claude 3 Opus: 41.4 (#207)
- GPT-5-Codex: —

| Benchmark | Claude 3 Opus | GPT-5-Codex |
|---|---|---|
| LMArena Non-English | 1258 | — |
| LMArena Chinese | 1248 | — |
| LMArena French | 1275 | — |
| LMArena German | 1258 | — |
| LMArena Japanese | 1204 | — |
| LMArena Korean | 1187 | — |
| LMArena Russian | 1280 | — |
| LMArena Spanish | 1246 | — |

## Instruction Following

- Claude 3 Opus: 64.1 (#228)
- GPT-5-Codex: —

| Benchmark | Claude 3 Opus | GPT-5-Codex |
|---|---|---|
| LiveBench Instruction Following | 63.9% | — |
| LMArena Instruction Following | 1248 | — |

## Long Context

- Claude 3 Opus: 38.2 (#202)
- GPT-5-Codex: —

| Benchmark | Claude 3 Opus | GPT-5-Codex |
|---|---|---|
| LMArena Longer Query | 1259 | — |

## Writing & Preference

- Claude 3 Opus: 47.2 (#213)
- GPT-5-Codex: —

| Benchmark | Claude 3 Opus | GPT-5-Codex |
|---|---|---|
| LMArena Text | 1262 | — |
| LMArena Creative Writing | 1235 | — |
| LMArena Multi-Turn | 1275 | — |
| LiveBench Language | 50.4% | — |

## FAQ

### Is Claude 3 Opus better than GPT-5-Codex?

GPT-5-Codex is the stronger model overall, scoring 37.9 to 29.5 on the Noometry Index.

### Is Claude 3 Opus or GPT-5-Codex better for coding?

GPT-5-Codex scores higher on coding benchmarks: 42.4 versus 32.9 in the Noometry coding category.

### How many benchmarks do Claude 3 Opus and GPT-5-Codex share?

1 benchmark has published results for both models. Claude 3 Opus has 46 scored results on Noometry and GPT-5-Codex has 3.