Model comparison
Claude Sonnet 4 vs Claude Sonnet 5.5
Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 40.8 on the Noometry Index.
Last verified . 19 shared benchmarks.
Summary
- They share 19 benchmarks with published results for both. Claude Sonnet 4 scores higher in 0 categories and Claude Sonnet 5.5 in 10 categories; 10 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Sonnet 5.5 leads 87.9 to 43.3.
- The biggest single-benchmark swing is CritPt: 0.3% for Claude Sonnet 4 and 31.4% for Claude Sonnet 5.5.
- Claude Sonnet 5.5 is cheaper at $2 / $10 per million input/output tokens, against $3 / $15 for Claude Sonnet 4.
- Claude Sonnet 5.5 accepts more context: 1M tokens versus 200K.
Side by side
| Claude Sonnet 4 | Claude Sonnet 5.5 | |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Noometry Index | 40.8 | 61.9 |
| Released | 2025-05-22 | 2026-09-28 |
| Weights | Proprietary | Proprietary |
| Context window | 200K | 1M |
| Max output | 64K | 128K |
| Input $ / M tokens | $3 | $2 |
| Output $ / M tokens | $15 | $10 |
| Results tracked | 58 | 32 |
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Category by category
Coding Claude Sonnet 5.5 leads
Claude Sonnet 4: 43.5 (#88), Claude Sonnet 5.5: 67.3 (#6)
| Benchmark | Claude Sonnet 4 | Claude Sonnet 5.5 |
|---|---|---|
| SciCode | 40% | 61% |
| LMArena Coding | 1414 | 1513 |
| ALE-Bench | 655.35 | 1,819 |
| FrontierCode | — | 52.1% |
| SWE-bench Verified (bash only) | 64.9% | — |
| Aider Polyglot | 61.3% | — |
| CursorBench | — | 55.5% |
| LMArena WebDev | — | 1774 |
| FrontierSWE | — | 61.9% |
| GSO | 4.9% | — |
| WeirdML | 46.1% | — |
Agentic & Tool Use Claude Sonnet 5.5 leads
Claude Sonnet 4: 38.5 (#31), Claude Sonnet 5.5: 45.0 (#16)
| Benchmark | Claude Sonnet 4 | Claude Sonnet 5.5 |
|---|---|---|
| APEX-Agents | — | 75.5% |
| TheAgentCompany | 33.1% | — |
| Cybench | 35% | — |
| DeepResearch Bench | 46.6% | — |
| OSWorld | 43.9% | — |
| METR Time Horizons | 62% | — |
Reasoning Claude Sonnet 5.5 leads
Claude Sonnet 4: 22.9 (#187), Claude Sonnet 5.5: 54.0 (#28)
| Benchmark | Claude Sonnet 4 | Claude Sonnet 5.5 |
|---|---|---|
| CritPt | 0.3% | 31.4% |
| LMArena Hard Prompts | 1372 | 1495 |
| Epoch Capabilities Index | 141.69 | 165.03 |
| ARC-AGI-2 | 5.9% | — |
| SimpleBench | 45.5% | — |
| Kagi LLM Benchmark | 73% | — |
| NYT Connections (extended) | — | 80.5% |
| ARC-AGI-1 | 40% | — |
| EnigmaEval | 3.1% | — |
| Mystery Game Puzzles | — | 65% |
| DTBench | 77.1% | — |
| LMCA | 29% | — |
| ForecastBench | 60.2 | — |
Math Claude Sonnet 5.5 leads
Claude Sonnet 4: 43.3 (#80), Claude Sonnet 5.5: 87.9 (#6)
| Benchmark | Claude Sonnet 4 | Claude Sonnet 5.5 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 71.1% | 100% |
| LMArena Math | 1375 | 1510 |
| FrontierMath (Tiers 1-3) | — | 88.8% |
| FrontierMath Tier 4 | — | 80.5% |
| ProofBench | — | 100% |
| Omni-MATH | 60.2% | — |
| MATH Level 5 | 84.4% | — |
| FrontierMath (Feb 2025 set) | 4.1% | — |
| FrontierMath Erdős | — | 2.9% |
| FrontierMath Tier 4 (v1) | 0% | — |
Knowledge Claude Sonnet 5.5 leads
Claude Sonnet 4: 41.8 (#108), Claude Sonnet 5.5: 66.0 (#12)
| Benchmark | Claude Sonnet 4 | Claude Sonnet 5.5 |
|---|---|---|
| GPQA Diamond | 79.2% | 95.6% |
| LMArena Expert | 1372 | 1540 |
| Humanity's Last Exam | 7.8% | — |
| SimpleQA Verified | — | 46.5% |
| MMLU-Pro | 84.3% | — |
| Confabulations | 13.2% | — |
| Vectara Hallucination Rate | 10.3% | — |
| GPQA (HELM) | 70.6% | — |
Multimodal Claude Sonnet 5.5 leads
Claude Sonnet 4: 26.2 (#121), Claude Sonnet 5.5: 51.5 (#6)
| Benchmark | Claude Sonnet 4 | Claude Sonnet 5.5 |
|---|---|---|
| LMArena Vision | 1191 | 1289 |
| GeoBench | 37% | — |
| VPCT | 34% | — |
| Furniture Assembly | — | 75% |
| MindCube | 44.8% | — |
Multilingual Claude Sonnet 5.5 leads
Claude Sonnet 4: 46.7 (#156), Claude Sonnet 5.5: 55.3 (#30)
| Benchmark | Claude Sonnet 4 | Claude Sonnet 5.5 |
|---|---|---|
| LMArena Non-English | 1333 | 1452 |
| LMArena Chinese | 1350 | 1522 |
| LMArena Russian | 1355 | 1451 |
| LMArena French | 1363 | — |
| LMArena German | 1331 | — |
| LMArena Japanese | 1302 | — |
| LMArena Korean | 1291 | — |
| LMArena Spanish | 1357 | — |
Instruction Following Claude Sonnet 5.5 leads
Claude Sonnet 4: 71.7 (#145), Claude Sonnet 5.5: 78.3 (#11)
| Benchmark | Claude Sonnet 4 | Claude Sonnet 5.5 |
|---|---|---|
| LMArena Instruction Following | 1376 | 1495 |
| IFEval | 84% | — |
Long Context Claude Sonnet 5.5 leads
Claude Sonnet 4: 33.7 (#259), Claude Sonnet 5.5: 45.9 (#28)
| Benchmark | Claude Sonnet 4 | Claude Sonnet 5.5 |
|---|---|---|
| LMArena Longer Query | 1398 | 1498 |
| Fiction.LiveBench | 46.9% | — |
Writing & Preference Claude Sonnet 5.5 leads
Claude Sonnet 4: 57.1 (#132), Claude Sonnet 5.5: 66.0 (#40)
| Benchmark | Claude Sonnet 4 | Claude Sonnet 5.5 |
|---|---|---|
| LMArena Text | 1351 | 1471 |
| LMArena Creative Writing | 1345 | 1465 |
| LMArena Multi-Turn | 1376 | 1474 |
| Short-Story Creative Writing | 81.4% | — |
| EQ-Bench Creative Writing | 1483 | — |
| WildBench | 83.8% | — |
Frequently asked questions
Is Claude Sonnet 4 better than Claude Sonnet 5.5?
Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 40.8 on the Noometry Index.
Which is cheaper, Claude Sonnet 4 or Claude Sonnet 5.5?
Claude Sonnet 5.5 is cheaper. It lists at $2 per million input tokens and $10 per million output tokens; Claude Sonnet 4 lists at $3 and $15.
Is Claude Sonnet 4 or Claude Sonnet 5.5 better for coding?
Claude Sonnet 5.5 scores higher on coding benchmarks: 67.3 versus 43.5 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 4 and Claude Sonnet 5.5 share?
19 benchmarks have published results for both models. Claude Sonnet 4 has 58 scored results on Noometry and Claude Sonnet 5.5 has 32.