Model comparison
Claude 3 Sonnet vs Claude Opus 5.5
Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 29.0 on the Noometry Index.
Last verified . 19 shared benchmarks.
Summary
- They share 19 benchmarks with published results for both. Claude 3 Sonnet scores higher in 0 categories and Claude Opus 5.5 in 9 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Opus 5.5 leads 91.8 to 10.7.
- The biggest single-benchmark swing is OTIS Mock AIME 2024-2025: 2.5% for Claude 3 Sonnet and 100% for Claude Opus 5.5.
Side by side
| Claude 3 Sonnet | Claude Opus 5.5 | |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Noometry Index | 29.0 | 68.6 |
| Released | 2024-02-29 | 2026-09-22 |
| Weights | Proprietary | Proprietary |
| Context window | — | 1M |
| Max output | — | 128K |
| Input $ / M tokens | — | $4 |
| Output $ / M tokens | — | $20 |
| Results tracked | 30 | 44 |
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Category by category
Coding Claude Opus 5.5 leads
Claude 3 Sonnet: 29.6 (#302), Claude Opus 5.5: 71.9 (#3)
| Benchmark | Claude 3 Sonnet | Claude Opus 5.5 |
|---|---|---|
| LMArena Coding | 1223 | 1547 |
| FrontierCode | — | 54.6% |
| CursorBench | — | 57.8% |
| LMArena WebDev | — | 1813 |
| FrontierSWE | — | 62.3% |
| SciCode | — | 66.9% |
| WeirdML | 10.2% | — |
| BigCodeBench Instruct | 42.7% | — |
| MirrorCode | — | 77.4% |
| BigCodeBench Complete | 53.8% | — |
| ALE-Bench | — | 2,147 |
| HumanEval+ | 64% | — |
| MBPP+ | 69.3% | — |
Agentic & Tool Use Not comparable
Claude 3 Sonnet: —, Claude Opus 5.5: 45.3 (#15)
| Benchmark | Claude 3 Sonnet | Claude Opus 5.5 |
|---|---|---|
| APEX-Agents | — | 73.5% |
| GDP.pdf | — | 30.6% |
| Vending-Bench 2 | — | 9,235 |
Reasoning Claude Opus 5.5 leads
Claude 3 Sonnet: 20.5 (#237), Claude Opus 5.5: 80.2 (#3)
| Benchmark | Claude 3 Sonnet | Claude Opus 5.5 |
|---|---|---|
| LMArena Hard Prompts | 1197 | 1535 |
| DTBench | 53.6% | 98.9% |
| Epoch Capabilities Index | 120.7 | 167.33 |
| ARC-AGI-2 | — | 93.3% |
| NYT Connections (extended) | — | 88.5% |
| ARC-AGI-1 | — | 98.5% |
| CritPt | — | 31.7% |
| EBR-Bench | — | 71.4% |
| Mystery Game Puzzles | — | 71% |
| LMCA | — | 68.2% |
| WinoGrande | 75.1% | — |
Math Claude Opus 5.5 leads
Claude 3 Sonnet: 10.7 (#310), Claude Opus 5.5: 91.8 (#3)
| Benchmark | Claude 3 Sonnet | Claude Opus 5.5 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 2.5% | 100% |
| LMArena Math | 1213 | 1506 |
| FrontierMath (Tiers 1-3) | — | 91.2% |
| FrontierMath Tier 4 | — | 95% |
| ProofBench | — | 100% |
| MATH Level 5 | 18.2% | — |
| FrontierMath Erdős | — | 2.9% |
Knowledge Claude Opus 5.5 leads
Claude 3 Sonnet: 21.1 (#276), Claude Opus 5.5: 66.4 (#10)
| Benchmark | Claude 3 Sonnet | Claude Opus 5.5 |
|---|---|---|
| GPQA Diamond | 40.6% | 90.6% |
| LMArena Expert | 1173 | 1547 |
| SimpleQA Verified | — | 72.2% |
| MMLU | 75.9% | — |
Multimodal Claude Opus 5.5 leads
Claude 3 Sonnet: 25.2 (#125), Claude Opus 5.5: 57.8 (#1)
| Benchmark | Claude 3 Sonnet | Claude Opus 5.5 |
|---|---|---|
| LMArena Vision | 984 | 1321 |
| Blueprint-Bench 2 | — | 51.2% |
| Furniture Assembly | — | 83.3% |
Multilingual Claude Opus 5.5 leads
Claude 3 Sonnet: 37.8 (#234), Claude Opus 5.5: 59.1 (#2)
| Benchmark | Claude 3 Sonnet | Claude Opus 5.5 |
|---|---|---|
| LMArena Non-English | 1205 | 1507 |
| LMArena Chinese | 1189 | 1588 |
| LMArena French | 1229 | 1514 |
| LMArena Russian | 1227 | 1520 |
| LMArena Spanish | 1204 | 1507 |
| LMArena German | 1204 | — |
| LMArena Japanese | 1131 | — |
| LMArena Korean | 1128 | — |
Instruction Following Claude Opus 5.5 leads
Claude 3 Sonnet: 62.8 (#235), Claude Opus 5.5: 80.0 (#3)
| Benchmark | Claude 3 Sonnet | Claude Opus 5.5 |
|---|---|---|
| LMArena Instruction Following | 1199 | 1537 |
Long Context Claude Opus 5.5 leads
Claude 3 Sonnet: 36.7 (#228), Claude Opus 5.5: 47.1 (#19)
| Benchmark | Claude 3 Sonnet | Claude Opus 5.5 |
|---|---|---|
| LMArena Longer Query | 1211 | 1532 |
Writing & Preference Claude Opus 5.5 leads
Claude 3 Sonnet: 42.1 (#238), Claude Opus 5.5: 78.2 (#3)
| Benchmark | Claude 3 Sonnet | Claude Opus 5.5 |
|---|---|---|
| LMArena Text | 1218 | 1515 |
| LMArena Creative Writing | 1186 | 1533 |
| LMArena Multi-Turn | 1227 | 1499 |
| EQ-Bench Creative Writing | — | 2050 |
Frequently asked questions
Is Claude 3 Sonnet better than Claude Opus 5.5?
Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 29.0 on the Noometry Index.
Is Claude 3 Sonnet or Claude Opus 5.5 better for coding?
Claude Opus 5.5 scores higher on coding benchmarks: 71.9 versus 29.6 in the Noometry coding category.
How many benchmarks do Claude 3 Sonnet and Claude Opus 5.5 share?
19 benchmarks have published results for both models. Claude 3 Sonnet has 30 scored results on Noometry and Claude Opus 5.5 has 44.