# Claude Opus 5.5 vs Step 3

> Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 40.5 on the Noometry Index.

- Canonical page: https://noometry.com/compare/claude-opus-5-5-vs-step-3
- Last updated: 2026-10-11
- Shared benchmarks: 14

## Summary

- They share 14 benchmarks with published results for both. Claude Opus 5.5 scores higher in 9 categories and Step 3 in 0 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Opus 5.5 leads 91.8 to 37.6.
- Step 3 has downloadable open weights; the other is API-only.

## Snapshot

| | Claude Opus 5.5 | Step 3 |
|---|---|---|
| Provider | Anthropic | StepFun |
| Noometry Index | 68.6 | 40.5 |
| Rank | 3 | 149 |
| Context | 1M | — |
| Input $/M | $4 | — |
| Output $/M | $20 | — |
| Weights | Proprietary | Open |

## Coding

- Claude Opus 5.5: 71.9 (#3)
- Step 3: 40.1 (#147)

| Benchmark | Claude Opus 5.5 | Step 3 |
|---|---|---|
| LMArena Coding | 1547 | 1367 |
| FrontierCode | 54.6% | — |
| CursorBench | 57.8% | — |
| LMArena WebDev | 1813 | — |
| FrontierSWE | 62.3% | — |
| SciCode | 66.9% | — |
| MirrorCode | 77.4% | — |
| ALE-Bench | 2,147 | — |

## Agentic & Tool Use

- Claude Opus 5.5: 45.3 (#15)
- Step 3: —

| Benchmark | Claude Opus 5.5 | Step 3 |
|---|---|---|
| APEX-Agents | 73.5% | — |
| GDP.pdf | 30.6% | — |
| Vending-Bench 2 | 9,235 | — |

## Reasoning

- Claude Opus 5.5: 80.2 (#3)
- Step 3: 28.4 (#105)

| Benchmark | Claude Opus 5.5 | Step 3 |
|---|---|---|
| LMArena Hard Prompts | 1535 | 1355 |
| ARC-AGI-2 | 93.3% | — |
| Kagi LLM Benchmark | — | 62.3% |
| NYT Connections (extended) | 88.5% | — |
| ARC-AGI-1 | 98.5% | — |
| CritPt | 31.7% | — |
| EBR-Bench | 71.4% | — |
| Mystery Game Puzzles | 71% | — |
| DTBench | 98.9% | — |
| LMCA | 68.2% | — |
| Epoch Capabilities Index | 167.33 | — |

## Math

- Claude Opus 5.5: 91.8 (#3)
- Step 3: 37.6 (#148)

| Benchmark | Claude Opus 5.5 | Step 3 |
|---|---|---|
| LMArena Math | 1506 | 1366 |
| FrontierMath (Tiers 1-3) | 91.2% | — |
| FrontierMath Tier 4 | 95% | — |
| OTIS Mock AIME 2024-2025 | 100% | — |
| ProofBench | 100% | — |
| FrontierMath Erdős | 2.9% | — |

## Knowledge

- Claude Opus 5.5: 66.4 (#10)
- Step 3: 36.8 (#164)

| Benchmark | Claude Opus 5.5 | Step 3 |
|---|---|---|
| LMArena Expert | 1547 | 1333 |
| GPQA Diamond | 90.6% | — |
| SimpleQA Verified | 72.2% | — |

## Multimodal

- Claude Opus 5.5: 57.8 (#1)
- Step 3: 35.5 (#86)

| Benchmark | Claude Opus 5.5 | Step 3 |
|---|---|---|
| LMArena Vision | 1321 | 1177 |
| Blueprint-Bench 2 | 51.2% | — |
| Furniture Assembly | 83.3% | — |

## Multilingual

- Claude Opus 5.5: 59.1 (#2)
- Step 3: 46.3 (#159)

| Benchmark | Claude Opus 5.5 | Step 3 |
|---|---|---|
| LMArena Non-English | 1507 | 1327 |
| LMArena Chinese | 1588 | 1397 |
| LMArena Russian | 1520 | 1331 |
| LMArena Spanish | 1507 | 1371 |
| LMArena French | 1514 | — |
| LMArena German | — | 1371 |
| LMArena Korean | — | 1269 |

## Instruction Following

- Claude Opus 5.5: 80.0 (#3)
- Step 3: 70.4 (#164)

| Benchmark | Claude Opus 5.5 | Step 3 |
|---|---|---|
| LMArena Instruction Following | 1537 | 1332 |

## Long Context

- Claude Opus 5.5: 47.1 (#19)
- Step 3: 40.3 (#157)

| Benchmark | Claude Opus 5.5 | Step 3 |
|---|---|---|
| LMArena Longer Query | 1532 | 1326 |

## Writing & Preference

- Claude Opus 5.5: 78.2 (#3)
- Step 3: 54.3 (#151)

| Benchmark | Claude Opus 5.5 | Step 3 |
|---|---|---|
| LMArena Text | 1515 | 1350 |
| LMArena Creative Writing | 1533 | 1321 |
| LMArena Multi-Turn | 1499 | 1341 |
| EQ-Bench Creative Writing | 2050 | — |

## FAQ

### Is Claude Opus 5.5 better than Step 3?

Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 40.5 on the Noometry Index.

### Is Claude Opus 5.5 or Step 3 better for coding?

Claude Opus 5.5 scores higher on coding benchmarks: 71.9 versus 40.1 in the Noometry coding category.

### How many benchmarks do Claude Opus 5.5 and Step 3 share?

14 benchmarks have published results for both models. Claude Opus 5.5 has 44 scored results on Noometry and Step 3 has 17.