# Claude Sonnet 5.5 vs o3-mini

> Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 36.7 on the Noometry Index. o3-mini costs 2.1× less per token, which makes it the better buy when Claude Sonnet 5.5's lead doesn't matter for your workload.

- Canonical page: https://noometry.com/compare/claude-sonnet-5-5-vs-o3-mini
- Last updated: 2026-10-10
- Shared benchmarks: 21

## Summary

- They share 21 benchmarks with published results for both. Claude Sonnet 5.5 scores higher in 9 categories and o3-mini in 0 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Sonnet 5.5 leads 87.9 to 28.1.
- The biggest single-benchmark swing is FrontierMath Tier 4: 80.5% for Claude Sonnet 5.5 and 0% for o3-mini.
- o3-mini is cheaper at $1.10 / $4.40 per million input/output tokens, against $2 / $10 for Claude Sonnet 5.5.
- Claude Sonnet 5.5 accepts more context: 1M tokens versus 200K.

## Snapshot

| | Claude Sonnet 5.5 | o3-mini |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 61.9 | 36.7 |
| Rank | 10 | 212 |
| Context | 1M | 200K |
| Input $/M | $2 | $1.10 |
| Output $/M | $10 | $4.40 |
| Weights | Proprietary | Proprietary |

## Coding

- Claude Sonnet 5.5: 67.3 (#6)
- o3-mini: 40.8 (#132)

| Benchmark | Claude Sonnet 5.5 | o3-mini |
|---|---|---|
| SciCode | 61% | 39.8% |
| LMArena Coding | 1513 | 1378 |
| FrontierCode | 52.1% | — |
| Aider Polyglot | — | 60.4% |
| CursorBench | 55.5% | — |
| LMArena WebDev | 1774 | — |
| FrontierSWE | 61.9% | — |
| GSO | — | 1.3% |
| WeirdML | — | 43.7% |
| LiveBench Coding | — | 82.7% |
| CadEval | — | 54% |
| ALE-Bench | 1,819 | — |

## Agentic & Tool Use

- Claude Sonnet 5.5: 45.0 (#16)
- o3-mini: 29.6 (#84)

| Benchmark | Claude Sonnet 5.5 | o3-mini |
|---|---|---|
| APEX-Agents | 75.5% | — |
| Cybench | — | 22.5% |

## Reasoning

- Claude Sonnet 5.5: 54.0 (#28)
- o3-mini: 16.3 (#305)

| Benchmark | Claude Sonnet 5.5 | o3-mini |
|---|---|---|
| CritPt | 31.4% | 0.3% |
| LMArena Hard Prompts | 1495 | 1366 |
| Mystery Game Puzzles | 65% | 7% |
| Epoch Capabilities Index | 165.03 | 140.34 |
| ARC-AGI-2 | — | 3% |
| SimpleBench | — | 22.8% |
| NYT Connections (extended) | 80.5% | — |
| ARC-AGI-1 | — | 34.5% |
| Chess Puzzles | — | 17% |
| LiveBench Reasoning | — | 89.6% |
| DTBench | — | 68.8% |
| LiveBench Data Analysis | — | 70.6% |
| LMCA | — | 19% |
| ForecastBench | — | 59.6 |
| LiveBench | — | 75.9% |

## Math

- Claude Sonnet 5.5: 87.9 (#6)
- o3-mini: 28.1 (#244)

| Benchmark | Claude Sonnet 5.5 | o3-mini |
|---|---|---|
| FrontierMath (Tiers 1-3) | 88.8% | 18.6% |
| FrontierMath Tier 4 | 80.5% | 0% |
| OTIS Mock AIME 2024-2025 | 100% | 76.9% |
| LMArena Math | 1510 | 1396 |
| ProofBench | 100% | — |
| LiveBench Math | — | 77.3% |
| MATH Level 5 | — | 96.5% |
| FrontierMath (Feb 2025 set) | — | 12.4% |
| FrontierMath Erdős | 2.9% | — |
| FrontierMath Tier 4 (v1) | — | 4.2% |

## Knowledge

- Claude Sonnet 5.5: 66.0 (#12)
- o3-mini: 38.3 (#146)

| Benchmark | Claude Sonnet 5.5 | o3-mini |
|---|---|---|
| GPQA Diamond | 95.6% | 77% |
| SimpleQA Verified | 46.5% | 15.3% |
| LMArena Expert | 1540 | 1364 |
| Confabulations | — | 17.9% |

## Multimodal

- Claude Sonnet 5.5: 51.5 (#6)
- o3-mini: —

| Benchmark | Claude Sonnet 5.5 | o3-mini |
|---|---|---|
| LMArena Vision | 1289 | — |
| Furniture Assembly | 75% | — |

## Multilingual

- Claude Sonnet 5.5: 55.3 (#30)
- o3-mini: 45.7 (#164)

| Benchmark | Claude Sonnet 5.5 | o3-mini |
|---|---|---|
| LMArena Non-English | 1452 | 1319 |
| LMArena Chinese | 1522 | 1379 |
| LMArena Russian | 1451 | 1304 |
| LMArena French | — | 1334 |
| LMArena German | — | 1303 |
| LMArena Japanese | — | 1286 |
| LMArena Korean | — | 1314 |
| LMArena Spanish | — | 1321 |

## Instruction Following

- Claude Sonnet 5.5: 78.3 (#11)
- o3-mini: 75.1 (#72)

| Benchmark | Claude Sonnet 5.5 | o3-mini |
|---|---|---|
| LMArena Instruction Following | 1495 | 1337 |
| LiveBench Instruction Following | — | 84.4% |

## Long Context

- Claude Sonnet 5.5: 45.9 (#28)
- o3-mini: 33.8 (#256)

| Benchmark | Claude Sonnet 5.5 | o3-mini |
|---|---|---|
| LMArena Longer Query | 1498 | 1343 |
| Fiction.LiveBench | — | 50% |

## Writing & Preference

- Claude Sonnet 5.5: 66.0 (#40)
- o3-mini: 50.3 (#182)

| Benchmark | Claude Sonnet 5.5 | o3-mini |
|---|---|---|
| LMArena Text | 1471 | 1337 |
| LMArena Creative Writing | 1465 | 1286 |
| LMArena Multi-Turn | 1474 | 1320 |
| Short-Story Creative Writing | — | 61.7% |
| LiveBench Language | — | 50.7% |

## FAQ

### Is Claude Sonnet 5.5 better than o3-mini?

Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 36.7 on the Noometry Index. o3-mini costs 2.1× less per token, which makes it the better buy when Claude Sonnet 5.5's lead doesn't matter for your workload.

### Which is cheaper, Claude Sonnet 5.5 or o3-mini?

o3-mini is cheaper. It lists at $1.10 per million input tokens and $4.40 per million output tokens; Claude Sonnet 5.5 lists at $2 and $10.

### Is Claude Sonnet 5.5 or o3-mini better for coding?

Claude Sonnet 5.5 scores higher on coding benchmarks: 67.3 versus 40.8 in the Noometry coding category.

### Which has the bigger context window?

Claude Sonnet 5.5 does, with 1M tokens against 200K.

### How many benchmarks do Claude Sonnet 5.5 and o3-mini share?

21 benchmarks have published results for both models. Claude Sonnet 5.5 has 32 scored results on Noometry and o3-mini has 51.