# Claude Opus 5.5 vs GPT-4o

> Claude Opus 5.5 is the stronger model overall, scoring 68.5 to 28.5 on the Noometry Index. GPT-4o costs 1.8× less per token, which makes it the better buy when Claude Opus 5.5's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/claude-opus-5-5-vs-gpt-4o
- Last updated: 2026-10-10
- Shared benchmarks: 20

## Summary

- They share 20 benchmarks with published results for both. Claude Opus 5.5 scores higher in 10 categories and GPT-4o in 0 categories; 10 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Opus 5.5 leads 92.4 to 10.2.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 100% for Claude Opus 5.5 and 6.4% for GPT-4o.
- GPT-4o is cheaper at $2.50 / $10 per million input/output tokens, against $4 / $20 for Claude Opus 5.5.
- Claude Opus 5.5 accepts more context: 1M tokens versus 128K.

## Snapshot

| | Claude Opus 5.5 | GPT-4o |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 68.5 | 28.5 |
| Rank | 3 | 316 |
| Context | 1M | 128K |
| Input $/M | $4 | $2.50 |
| Output $/M | $20 | $10 |
| Weights | Proprietary | Proprietary |

## Coding

- Claude Opus 5.5: 71.4 (#1)
- GPT-4o: 25.1 (#323)

| Benchmark | Claude Opus 5.5 | GPT-4o |
|---|---|---|
| LMArena Coding | 1545 | 1297 |
| SWE-bench Verified | — | 31% |
| FrontierCode | 54.4% | — |
| SWE-bench Verified (bash only) | — | 21.6% |
| Aider Polyglot | — | 45.3% |
| CursorBench | 57.8% | — |
| LMArena WebDev | 1820 | — |
| FrontierSWE | 62.3% | — |
| SciCode | 66.9% | — |
| GSO | — | 0% |
| WeirdML | — | 25.1% |
| BigCodeBench Instruct | — | 51.1% |
| LiveBench Coding | — | 51.4% |
| MirrorCode | 77.4% | — |
| BigCodeBench Complete | — | 61.1% |
| CadEval | — | 26% |
| HumanEval+ | — | 87.2% |
| MBPP+ | — | 72.2% |

## Agentic & Tool Use

- Claude Opus 5.5: 45.3 (#13)
- GPT-4o: 20.8 (#133)

| Benchmark | Claude Opus 5.5 | GPT-4o |
|---|---|---|
| APEX-Agents | 73.5% | — |
| GDPval | — | 9.9% |
| TheAgentCompany | — | 8.6% |
| Cybench | — | 12.5% |
| BALROG | — | 32.3% |
| GDP.pdf | 30.6% | — |
| LMArena Search | — | 1006 |
| METR Time Horizons | — | 40.8% |

## Reasoning

- Claude Opus 5.5: 79.5 (#2)
- GPT-4o: 9.4 (#338)

| Benchmark | Claude Opus 5.5 | GPT-4o |
|---|---|---|
| ARC-AGI-2 | 92.5% | 0% |
| ARC-AGI-1 | 97.5% | 4.5% |
| CritPt | 31.7% | 0% |
| LMArena Hard Prompts | 1545 | 1281 |
| DTBench | 98.9% | 64.5% |
| LMCA | 68.2% | 16.6% |
| SimpleBench | — | 17.8% |
| NYT Connections (extended) | 88.5% | — |
| Chess Puzzles | — | 13% |
| EnigmaEval | — | 0.8% |
| EBR-Bench | 71.4% | — |
| LiveBench Reasoning | — | 55.8% |
| Mystery Game Puzzles | 71% | — |
| LiveBench Data Analysis | — | 60.9% |
| Epoch Capabilities Index | — | 128.97 |
| ForecastBench | — | 57.7 |
| LiveBench | — | 55.3% |

## Math

- Claude Opus 5.5: 92.4 (#2)
- GPT-4o: 10.2 (#303)

| Benchmark | Claude Opus 5.5 | GPT-4o |
|---|---|---|
| FrontierMath (Tiers 1-3) | 91.2% | 0.4% |
| OTIS Mock AIME 2024-2025 | 100% | 6.4% |
| FrontierMath Tier 4 | 95% | — |
| ProofBench | 100% | — |
| Omni-MATH | — | 29.3% |
| LiveBench Math | — | 49.5% |
| LMArena Math | — | 1285 |
| MATH Level 5 | — | 53.3% |
| FrontierMath (Feb 2025 set) | — | 0.3% |

## Knowledge

- Claude Opus 5.5: 66.6 (#9)
- GPT-4o: 28.8 (#235)

| Benchmark | Claude Opus 5.5 | GPT-4o |
|---|---|---|
| GPQA Diamond | 90.6% | 49.2% |
| SimpleQA Verified | 72.2% | 26% |
| LMArena Expert | 1564 | 1250 |
| Humanity's Last Exam | — | 2.7% |
| MMLU-Pro | — | 71.3% |
| Confabulations | — | 15.3% |
| Vectara Hallucination Rate | — | 9.6% |
| GPQA (HELM) | — | 52% |
| MMLU | — | 88.1% |

## Multimodal

- Claude Opus 5.5: 56.5 (#2)
- GPT-4o: 33.9 (#85)

| Benchmark | Claude Opus 5.5 | GPT-4o |
|---|---|---|
| LMArena Vision | — | 1137 |
| Video-MME | — | 71.9% |
| GeoBench | — | 71% |
| VPCT | — | 40% |
| Furniture Assembly | 83.3% | — |
| ScienceQA | — | 88.5% |

## Multilingual

- Claude Opus 5.5: 59.8 (#1)
- GPT-4o: 43.4 (#181)

| Benchmark | Claude Opus 5.5 | GPT-4o |
|---|---|---|
| LMArena Non-English | 1513 | 1283 |
| LMArena Chinese | 1572 | 1277 |
| LMArena Russian | 1532 | 1286 |
| LMArena French | — | 1303 |
| LMArena German | — | 1282 |
| LMArena Japanese | — | 1257 |
| LMArena Korean | — | 1234 |
| LMArena Spanish | — | 1292 |

## Instruction Following

- Claude Opus 5.5: 80.1 (#2)
- GPT-4o: 66.8 (#202)

| Benchmark | Claude Opus 5.5 | GPT-4o |
|---|---|---|
| LMArena Instruction Following | 1535 | 1278 |
| LiveBench Instruction Following | — | 68.6% |
| IFEval | — | 81.7% |

## Long Context

- Claude Opus 5.5: 47.3 (#18)
- GPT-4o: 39.4 (#174)

| Benchmark | Claude Opus 5.5 | GPT-4o |
|---|---|---|
| LMArena Longer Query | 1540 | 1289 |
| Fiction.LiveBench | — | 66.7% |

## Writing & Preference

- Claude Opus 5.5: 78.7 (#3)
- GPT-4o: 52.8 (#160)

| Benchmark | Claude Opus 5.5 | GPT-4o |
|---|---|---|
| LMArena Text | 1518 | 1300 |
| LMArena Creative Writing | 1538 | 1291 |
| LMArena Multi-Turn | 1520 | 1302 |
| Short-Story Creative Writing | — | 81.8% |
| EQ-Bench Creative Writing | 2050 | — |
| WildBench | — | 82.8% |
| LiveBench Language | — | 47.6% |

## FAQ

### Is Claude Opus 5.5 better than GPT-4o?

Claude Opus 5.5 is the stronger model overall, scoring 68.5 to 28.5 on the Noometry Index. GPT-4o costs 1.8× less per token, which makes it the better buy when Claude Opus 5.5's lead doesn't matter for your workload.

### Which is cheaper, Claude Opus 5.5 or GPT-4o?

GPT-4o is cheaper. It lists at $2.50 per million input tokens and $10 per million output tokens; Claude Opus 5.5 lists at $4 and $20.

### Is Claude Opus 5.5 or GPT-4o better for coding?

Claude Opus 5.5 scores higher on coding benchmarks: 71.4 versus 25.1 in the Noometry coding category.

### Which has the bigger context window?

Claude Opus 5.5 does, with 1M tokens against 128K.

### How many benchmarks do Claude Opus 5.5 and GPT-4o share?

20 benchmarks have published results for both models. Claude Opus 5.5 has 35 scored results on Noometry and GPT-4o has 72.