# Claude 2.1 vs GPT-5.5 Instant

> GPT-5.5 Instant is the stronger model overall, scoring 42.7 to 25.2 on the Noometry Index.

- Canonical page: https://noometry.com/compare/claude-2-1-vs-gpt-5-5-instant
- Last updated: 2026-10-10
- Shared benchmarks: 3

## Summary

- They share 3 benchmarks with published results for both. Claude 2.1 scores higher in 0 categories and GPT-5.5 Instant in 4 categories; 4 gaps are clear of the uncertainty.
- The widest gap is in knowledge, where GPT-5.5 Instant leads 48.9 to 15.4.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 1.9% for Claude 2.1 and 68.1% for GPT-5.5 Instant.

## Snapshot

| | Claude 2.1 | GPT-5.5 Instant |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 25.2 | 42.7 |
| Rank | 345 | 110 |
| Context | — | — |
| Input $/M | — | — |
| Output $/M | — | — |
| Weights | Proprietary | Proprietary |

## Coding

- Claude 2.1: 26.2 (#327)
- GPT-5.5 Instant: 44.3 (#74)

| Benchmark | Claude 2.1 | GPT-5.5 Instant |
|---|---|---|
| SciCode | — | 48.6% |
| WeirdML | 7.1% | — |
| LMArena Coding | — | 1433 |

## Reasoning

- Claude 2.1: 21.4 (#221)
- GPT-5.5 Instant: 24.9 (#155)

| Benchmark | Claude 2.1 | GPT-5.5 Instant |
|---|---|---|
| Epoch Capabilities Index | 119.27 | 142.52 |
| CritPt | — | 0% |
| Chess Puzzles | — | 12% |
| LMArena Hard Prompts | — | 1426 |
| DTBench | 51% | — |
| ForecastBench | 54.2 | — |

## Math

- Claude 2.1: 10.2 (#315)
- GPT-5.5 Instant: 26.5 (#259)

| Benchmark | Claude 2.1 | GPT-5.5 Instant |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 1.9% | 68.1% |
| FrontierMath (Tiers 1-3) | — | 26.3% |
| FrontierMath Tier 4 | — | 2.4% |
| LMArena Math | — | 1420 |

## Knowledge

- Claude 2.1: 15.4 (#292)
- GPT-5.5 Instant: 48.9 (#74)

| Benchmark | Claude 2.1 | GPT-5.5 Instant |
|---|---|---|
| GPQA Diamond | 33% | 82.5% |
| LMArena Expert | — | 1409 |
| MMLU | 73.5% | — |

## Multimodal

- Claude 2.1: —
- GPT-5.5 Instant: 40.0 (#52)

| Benchmark | Claude 2.1 | GPT-5.5 Instant |
|---|---|---|
| LMArena Vision | — | 1250 |
| LMArena Document | — | 1403 |

## Multilingual

- Claude 2.1: —
- GPT-5.5 Instant: 52.8 (#80)

| Benchmark | Claude 2.1 | GPT-5.5 Instant |
|---|---|---|
| LMArena Non-English | — | 1417 |
| LMArena Chinese | — | 1456 |
| LMArena French | — | 1428 |
| LMArena German | — | 1411 |
| LMArena Japanese | — | 1408 |
| LMArena Korean | — | 1392 |
| LMArena Russian | — | 1431 |
| LMArena Spanish | — | 1429 |

## Instruction Following

- Claude 2.1: —
- GPT-5.5 Instant: 74.2 (#100)

| Benchmark | Claude 2.1 | GPT-5.5 Instant |
|---|---|---|
| LMArena Instruction Following | — | 1406 |

## Long Context

- Claude 2.1: —
- GPT-5.5 Instant: 43.4 (#96)

| Benchmark | Claude 2.1 | GPT-5.5 Instant |
|---|---|---|
| LMArena Longer Query | — | 1422 |

## Writing & Preference

- Claude 2.1: —
- GPT-5.5 Instant: 61.8 (#85)

| Benchmark | Claude 2.1 | GPT-5.5 Instant |
|---|---|---|
| LMArena Text | — | 1419 |
| LMArena Creative Writing | — | 1419 |
| LMArena Multi-Turn | — | 1433 |

## FAQ

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

GPT-5.5 Instant is the stronger model overall, scoring 42.7 to 25.2 on the Noometry Index.

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

GPT-5.5 Instant scores higher on coding benchmarks: 44.3 versus 26.2 in the Noometry coding category.

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

3 benchmarks have published results for both models. Claude 2.1 has 7 scored results on Noometry and GPT-5.5 Instant has 27.