# Claude 2.1 vs GPT-5.5 Pro

> GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 24.9 on the Noometry Index.

- Canonical page: https://noometry.com/compare/claude-2-1-vs-gpt-5-5-pro
- Last updated: 2026-10-10
- Shared benchmarks: 4

## Summary

- They share 4 benchmarks with published results for both. Claude 2.1 scores higher in 0 categories and GPT-5.5 Pro in 3 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in math, where GPT-5.5 Pro leads 83.8 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 Pro.

## Snapshot

| | Claude 2.1 | GPT-5.5 Pro |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 24.9 | 64.3 |
| Rank | 340 | 7 |
| Context | — | 1.05M |
| Input $/M | — | $30 |
| Output $/M | — | $180 |
| Weights | Proprietary | Proprietary |

## Coding

- Claude 2.1: 25.8 (#322)
- GPT-5.5 Pro: —

| Benchmark | Claude 2.1 | GPT-5.5 Pro |
|---|---|---|
| WeirdML | 7.1% | — |

## Reasoning

- Claude 2.1: 20.6 (#216)
- GPT-5.5 Pro: 73.6 (#7)

| Benchmark | Claude 2.1 | GPT-5.5 Pro |
|---|---|---|
| DTBench | 51% | 96% |
| Epoch Capabilities Index | 119.22 | 162.45 |
| ARC-AGI-2 | — | 84.6% |
| SimpleBench | — | 76.9% |
| ARC-AGI-1 | — | 96.5% |
| CritPt | — | 30.6% |
| Chess Puzzles | — | 64% |
| LMCA | — | 53.9% |
| ForecastBench | 54.2 | — |

## Math

- Claude 2.1: 9.6 (#309)
- GPT-5.5 Pro: 83.8 (#8)

| Benchmark | Claude 2.1 | GPT-5.5 Pro |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 1.9% | 100% |
| FrontierMath (Tiers 1-3) | — | 87.7% |
| FrontierMath Tier 4 | — | 78% |
| FrontierMath (Feb 2025 set) | — | 52.4% |
| FrontierMath Tier 4 (v1) | — | 39.6% |

## Knowledge

- Claude 2.1: 15.5 (#287)
- GPT-5.5 Pro: 64.2 (#17)

| Benchmark | Claude 2.1 | GPT-5.5 Pro |
|---|---|---|
| GPQA Diamond | 33% | 93.9% |
| MMLU | 73.5% | — |

## FAQ

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

GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 24.9 on the Noometry Index.

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

4 benchmarks have published results for both models. Claude 2.1 has 7 scored results on Noometry and GPT-5.5 Pro has 14.