Model comparison
Claude 2.1 vs GPT-5.5 Pro
GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 25.2 on the Noometry Index.
Last verified . 4 shared benchmarks.
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 84.0 to 10.2.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 1.9% for Claude 2.1 and 100% for GPT-5.5 Pro.
Side by side
| Claude 2.1 | GPT-5.5 Pro | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 25.2 | 64.3 |
| Released | 2023-11-21 | 2026-04-23 |
| Weights | Proprietary | Proprietary |
| Context window | — | 1.05M |
| Max output | — | 128K |
| Input $ / M tokens | — | $30 |
| Output $ / M tokens | — | $180 |
| Results tracked | 7 | 14 |
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Category by category
Coding Not comparable
Claude 2.1: 26.2 (#327), GPT-5.5 Pro: —
| Benchmark | Claude 2.1 | GPT-5.5 Pro |
|---|---|---|
| WeirdML | 7.1% | — |
Reasoning GPT-5.5 Pro leads
Claude 2.1: 21.4 (#221), GPT-5.5 Pro: 73.3 (#10)
| Benchmark | Claude 2.1 | GPT-5.5 Pro |
|---|---|---|
| DTBench | 51% | 96% |
| Epoch Capabilities Index | 119.27 | 162.07 |
| 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 GPT-5.5 Pro leads
Claude 2.1: 10.2 (#315), GPT-5.5 Pro: 84.0 (#10)
| 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 GPT-5.5 Pro leads
Claude 2.1: 15.4 (#292), GPT-5.5 Pro: 64.1 (#19)
| Benchmark | Claude 2.1 | GPT-5.5 Pro |
|---|---|---|
| GPQA Diamond | 33% | 93.9% |
| MMLU | 73.5% | — |
Frequently asked questions
Is Claude 2.1 better than GPT-5.5 Pro?
GPT-5.5 Pro is the stronger model overall, scoring 64.3 to 25.2 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.