# Claude 2.1 vs GPT-5.5

> GPT-5.5 is the stronger model overall, scoring 63.4 to 24.9 on the Noometry Index.

- Canonical page: https://noometry.com/compare/claude-2-1-vs-gpt-5-5
- Last updated: 2026-10-10
- Shared benchmarks: 6

## Summary

- They share 6 benchmarks with published results for both. Claude 2.1 scores higher in 0 categories and GPT-5.5 in 4 categories; 4 gaps are clear of the uncertainty.
- The widest gap is in math, where GPT-5.5 leads 81.5 to 9.6.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 1.9% for Claude 2.1 and 100% for GPT-5.5.

## Snapshot

| | Claude 2.1 | GPT-5.5 |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 24.9 | 63.4 |
| Rank | 340 | 8 |
| Context | — | 1.05M |
| Input $/M | — | $5 |
| Output $/M | — | $30 |
| Weights | Proprietary | Proprietary |

## Coding

- Claude 2.1: 25.8 (#322)
- GPT-5.5: 58.3 (#13)

| Benchmark | Claude 2.1 | GPT-5.5 |
|---|---|---|
| WeirdML | 7.1% | 84.9% |
| SWE-bench Verified | — | 80.6% |
| DeepSWE | — | 67% |
| FrontierCode | — | 43% |
| LMArena WebDev | — | 1512 |
| SciCode | — | 56.1% |
| GSO | — | 40.2% |
| LMArena Coding | — | 1494 |
| MirrorCode | — | 10% |
| ALE-Bench | — | 1,943 |

## Agentic & Tool Use

- Claude 2.1: —
- GPT-5.5: 50.7 (#6)

| Benchmark | Claude 2.1 | GPT-5.5 |
|---|---|---|
| Terminal-Bench | — | 84.7% |
| APEX-Agents | — | 55.1% |
| OSWorld 2.0 | — | 13% |
| Remote Labor Index | — | 6.3% |
| τ²-bench Banking | — | 44.6% |
| DeepResearch Bench | — | 54% |
| PostTrainBench | — | 27.2% |
| ExploitBench | — | 47.4% |
| GBAEval | — | 53.2% |
| GDP.pdf | — | 26% |
| LMArena Search | — | 1242 |
| Vending-Bench 2 | — | 7,524 |

## Reasoning

- Claude 2.1: 20.6 (#216)
- GPT-5.5: 72.7 (#8)

| Benchmark | Claude 2.1 | GPT-5.5 |
|---|---|---|
| DTBench | 51% | 96% |
| Epoch Capabilities Index | 119.22 | 159.25 |
| ForecastBench | 54.2 | 60.6 |
| ARC-AGI-2 | — | 85% |
| SimpleBench | — | 69% |
| Kagi LLM Benchmark | — | 88.8% |
| NYT Connections (extended) | — | 96.2% |
| ARC-AGI-1 | — | 95% |
| CritPt | — | 27.1% |
| Chess Puzzles | — | 54% |
| EBR-Bench | — | 34.3% |
| LMArena Hard Prompts | — | 1489 |
| Mystery Game Puzzles | — | 56% |
| LMCA | — | 54.3% |
| Surface Evolver Bench | — | 88.1% |
| Bench to the Future 3 | — | 0.14 |

## Math

- Claude 2.1: 9.6 (#309)
- GPT-5.5: 81.5 (#9)

| Benchmark | Claude 2.1 | GPT-5.5 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 1.9% | 100% |
| FrontierMath (Tiers 1-3) | — | 85.3% |
| FrontierMath Tier 4 | — | 72.5% |
| MathArena Final-Answer Competitions | — | 94.3% |
| ProofBench | — | 50% |
| LMArena Math | — | 1486 |
| FrontierMath (Feb 2025 set) | — | 51.7% |
| FrontierMath Erdős | — | 0% |
| FrontierMath Tier 4 (v1) | — | 35.4% |

## Knowledge

- Claude 2.1: 15.5 (#287)
- GPT-5.5: 64.4 (#14)

| Benchmark | Claude 2.1 | GPT-5.5 |
|---|---|---|
| GPQA Diamond | 33% | 94% |
| SimpleQA Verified | — | 63% |
| Vectara Hallucination Rate | — | 9.3% |
| LMArena Expert | — | 1508 |
| MMLU | 73.5% | — |

## Multimodal

- Claude 2.1: —
- GPT-5.5: 47.1 (#11)

| Benchmark | Claude 2.1 | GPT-5.5 |
|---|---|---|
| LMArena Vision | — | 1297 |
| Blueprint-Bench 2 | — | 36.2% |
| Furniture Assembly | — | 44.2% |
| LMArena Document | — | 1486 |

## Multilingual

- Claude 2.1: —
- GPT-5.5: 56.5 (#19)

| Benchmark | Claude 2.1 | GPT-5.5 |
|---|---|---|
| LMArena Non-English | — | 1467 |
| LMArena Chinese | — | 1535 |
| LMArena French | — | 1486 |
| LMArena German | — | 1478 |
| LMArena Japanese | — | 1498 |
| LMArena Korean | — | 1461 |
| LMArena Russian | — | 1473 |
| LMArena Spanish | — | 1469 |

## Instruction Following

- Claude 2.1: —
- GPT-5.5: 77.7 (#18)

| Benchmark | Claude 2.1 | GPT-5.5 |
|---|---|---|
| LMArena Instruction Following | — | 1479 |

## Long Context

- Claude 2.1: —
- GPT-5.5: 48.3 (#12)

| Benchmark | Claude 2.1 | GPT-5.5 |
|---|---|---|
| CL-bench Life | — | 22.2% |
| LMArena Longer Query | — | 1484 |

## Writing & Preference

- Claude 2.1: —
- GPT-5.5: 72.8 (#13)

| Benchmark | Claude 2.1 | GPT-5.5 |
|---|---|---|
| LMArena Text | — | 1471 |
| LMArena Creative Writing | — | 1455 |
| EQ-Bench Creative Writing | — | 1844 |
| EQ-Bench 4 | — | 1315 |
| LMArena Multi-Turn | — | 1477 |

## FAQ

### Is Claude 2.1 better than GPT-5.5?

GPT-5.5 is the stronger model overall, scoring 63.4 to 24.9 on the Noometry Index.

### Is Claude 2.1 or GPT-5.5 better for coding?

GPT-5.5 scores higher on coding benchmarks: 58.3 versus 25.8 in the Noometry coding category.

### How many benchmarks do Claude 2.1 and GPT-5.5 share?

6 benchmarks have published results for both models. Claude 2.1 has 7 scored results on Noometry and GPT-5.5 has 71.