# Claude 2.1 vs Claude Sonnet 5.5

> Claude Sonnet 5.5 is the stronger model overall, scoring 60.5 to 24.9 on the Noometry Index.

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

## Summary

- They share 2 benchmarks with published results for both. Claude 2.1 scores higher in 0 categories and Claude Sonnet 5.5 in 4 categories; 4 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Sonnet 5.5 leads 88.7 to 9.6.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 1.9% for Claude 2.1 and 100% for Claude Sonnet 5.5.

## Snapshot

| | Claude 2.1 | Claude Sonnet 5.5 |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Noometry Index | 24.9 | 60.5 |
| Rank | 340 | 10 |
| Context | — | 1M |
| Input $/M | — | $2 |
| Output $/M | — | $10 |
| Weights | Proprietary | Proprietary |

## Coding

- Claude 2.1: 25.8 (#322)
- Claude Sonnet 5.5: 65.5 (#6)

| Benchmark | Claude 2.1 | Claude Sonnet 5.5 |
|---|---|---|
| FrontierCode | — | 52.1% |
| CursorBench | — | 55.5% |
| LMArena WebDev | — | 1699 |
| FrontierSWE | — | 61.9% |
| SciCode | — | 61% |
| WeirdML | 7.1% | — |
| ALE-Bench | — | 1,819 |

## Agentic & Tool Use

- Claude 2.1: —
- Claude Sonnet 5.5: 44.9 (#14)

| Benchmark | Claude 2.1 | Claude Sonnet 5.5 |
|---|---|---|
| APEX-Agents | — | 75.5% |

## Reasoning

- Claude 2.1: 20.6 (#216)
- Claude Sonnet 5.5: 52.4 (#29)

| Benchmark | Claude 2.1 | Claude Sonnet 5.5 |
|---|---|---|
| CritPt | — | 31.4% |
| Mystery Game Puzzles | — | 65% |
| DTBench | 51% | — |
| Epoch Capabilities Index | 119.22 | — |
| ForecastBench | 54.2 | — |

## Math

- Claude 2.1: 9.6 (#309)
- Claude Sonnet 5.5: 88.7 (#4)

| Benchmark | Claude 2.1 | Claude Sonnet 5.5 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 1.9% | 100% |
| FrontierMath (Tiers 1-3) | — | 88.8% |
| FrontierMath Tier 4 | — | 80.5% |
| ProofBench | — | 100% |

## Knowledge

- Claude 2.1: 15.5 (#287)
- Claude Sonnet 5.5: 66.0 (#11)

| Benchmark | Claude 2.1 | Claude Sonnet 5.5 |
|---|---|---|
| GPQA Diamond | 33% | 95.6% |
| SimpleQA Verified | — | 46.5% |
| MMLU | 73.5% | — |

## Multimodal

- Claude 2.1: —
- Claude Sonnet 5.5: 53.2 (#5)

| Benchmark | Claude 2.1 | Claude Sonnet 5.5 |
|---|---|---|
| Furniture Assembly | — | 75% |

## FAQ

### Is Claude 2.1 better than Claude Sonnet 5.5?

Claude Sonnet 5.5 is the stronger model overall, scoring 60.5 to 24.9 on the Noometry Index.

### Is Claude 2.1 or Claude Sonnet 5.5 better for coding?

Claude Sonnet 5.5 scores higher on coding benchmarks: 65.5 versus 25.8 in the Noometry coding category.

### How many benchmarks do Claude 2.1 and Claude Sonnet 5.5 share?

2 benchmarks have published results for both models. Claude 2.1 has 7 scored results on Noometry and Claude Sonnet 5.5 has 16.