Model comparison
Claude Opus 4.8 vs Claude Sonnet 5.5
Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 60.7 on the Noometry Index.
Last verified . 29 shared benchmarks.
Summary
- They share 29 benchmarks with published results for both. Claude Opus 4.8 scores higher in 3 categories and Claude Sonnet 5.5 in 7 categories; 7 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Claude Opus 4.8 leads 64.7 to 54.0.
- The biggest single-benchmark swing is Furniture Assembly: 42.5% for Claude Opus 4.8 and 75% for Claude Sonnet 5.5.
- Claude Sonnet 5.5 is cheaper at $2 / $10 per million input/output tokens, against $5 / $25 for Claude Opus 4.8.
Side by side
| Claude Opus 4.8 | Claude Sonnet 5.5 | |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Noometry Index | 60.7 | 61.9 |
| Released | 2026-05-28 | 2026-09-28 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 1M |
| Max output | 128K | 128K |
| Input $ / M tokens | $5 | $2 |
| Output $ / M tokens | $25 | $10 |
| Results tracked | 65 | 32 |
Sponsored placements are available on pages like this one. Advertise on Noometry
Category by category
Coding Claude Sonnet 5.5 leads
Claude Opus 4.8: 59.9 (#12), Claude Sonnet 5.5: 67.3 (#6)
| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 |
|---|---|---|
| FrontierCode | 46.5% | 52.1% |
| LMArena WebDev | 1556 | 1774 |
| SciCode | 53.5% | 61% |
| LMArena Coding | 1490 | 1513 |
| ALE-Bench | 1,564 | 1,819 |
| DeepSWE | 59% | — |
| CursorBench | — | 55.5% |
| FrontierSWE | — | 61.9% |
| GSO | 47.1% | — |
| WeirdML | 82.9% | — |
Agentic & Tool Use Claude Opus 4.8 leads
Claude Opus 4.8: 47.6 (#11), Claude Sonnet 5.5: 45.0 (#16)
| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 |
|---|---|---|
| APEX-Agents | 48.9% | 75.5% |
| OSWorld 2.0 | 20.6% | — |
| Remote Labor Index | 8.3% | — |
| τ²-bench Banking | 39.7% | — |
| DeepResearch Bench | 50.2% | — |
| PostTrainBench | 33.8% | — |
| GBAEval | 70.9% | — |
| GDP.pdf | 24% | — |
| LMArena Search | 1204 | — |
| Vending-Bench 2 | 5,787 | — |
Reasoning Claude Opus 4.8 leads
Claude Opus 4.8: 64.7 (#16), Claude Sonnet 5.5: 54.0 (#28)
| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 |
|---|---|---|
| NYT Connections (extended) | 91.1% | 80.5% |
| CritPt | 20.9% | 31.4% |
| LMArena Hard Prompts | 1482 | 1495 |
| Mystery Game Puzzles | 36% | 65% |
| Epoch Capabilities Index | 158.21 | 165.03 |
| ARC-AGI-2 | 72.1% | — |
| SimpleBench | 64.8% | — |
| Kagi LLM Benchmark | 88.8% | — |
| ARC-AGI-1 | 92.5% | — |
| Chess Puzzles | 34% | — |
| EnigmaEval | 23.5% | — |
| EBR-Bench | 28.6% | — |
| DTBench | 94.9% | — |
| LMCA | 57.5% | — |
| Surface Evolver Bench | 87.5% | — |
| Bench to the Future 3 | 0.14 | — |
| ForecastBench | 59.9 | — |
Math Claude Sonnet 5.5 leads
Claude Opus 4.8: 78.4 (#13), Claude Sonnet 5.5: 87.9 (#6)
| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 80% | 88.8% |
| FrontierMath Tier 4 | 56.1% | 80.5% |
| OTIS Mock AIME 2024-2025 | 98.3% | 100% |
| ProofBench | 69% | 100% |
| LMArena Math | 1487 | 1510 |
| MathArena Final-Answer Competitions | 91.8% | — |
| FrontierMath (Feb 2025 set) | 47.2% | — |
| FrontierMath Erdős | — | 2.9% |
| FrontierMath Tier 4 (v1) | 31.3% | — |
Knowledge Claude Sonnet 5.5 leads
Claude Opus 4.8: 61.3 (#29), Claude Sonnet 5.5: 66.0 (#12)
| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 |
|---|---|---|
| GPQA Diamond | 91% | 95.6% |
| SimpleQA Verified | 53% | 46.5% |
| LMArena Expert | 1502 | 1540 |
Multimodal Claude Sonnet 5.5 leads
Claude Opus 4.8: 42.9 (#26), Claude Sonnet 5.5: 51.5 (#6)
| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 |
|---|---|---|
| LMArena Vision | 1294 | 1289 |
| Furniture Assembly | 42.5% | 75% |
| Blueprint-Bench 2 | 14.5% | — |
| LMArena Document | 1475 | — |
Multilingual Too close to call
Claude Opus 4.8: 55.2 (#33), Claude Sonnet 5.5: 55.3 (#30)
| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 |
|---|---|---|
| LMArena Non-English | 1450 | 1452 |
| LMArena Chinese | 1507 | 1522 |
| LMArena Russian | 1474 | 1451 |
| LMArena French | 1481 | — |
| LMArena German | 1472 | — |
| LMArena Japanese | 1440 | — |
| LMArena Korean | 1432 | — |
| LMArena Spanish | 1466 | — |
Instruction Following Too close to call
Claude Opus 4.8: 77.4 (#24), Claude Sonnet 5.5: 78.3 (#11)
| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 |
|---|---|---|
| LMArena Instruction Following | 1476 | 1495 |
Long Context Too close to call
Claude Opus 4.8: 45.4 (#35), Claude Sonnet 5.5: 45.9 (#28)
| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 |
|---|---|---|
| LMArena Longer Query | 1483 | 1498 |
Writing & Preference Claude Opus 4.8 leads
Claude Opus 4.8: 72.0 (#16), Claude Sonnet 5.5: 66.0 (#40)
| Benchmark | Claude Opus 4.8 | Claude Sonnet 5.5 |
|---|---|---|
| LMArena Text | 1461 | 1471 |
| LMArena Creative Writing | 1454 | 1465 |
| LMArena Multi-Turn | 1476 | 1474 |
| EQ-Bench Creative Writing | 1840 | — |
| EQ-Bench 4 | 1281 | — |
Frequently asked questions
Is Claude Opus 4.8 better than Claude Sonnet 5.5?
Claude Sonnet 5.5 is the stronger model overall, scoring 61.9 to 60.7 on the Noometry Index.
Which is cheaper, Claude Opus 4.8 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 Opus 4.8 lists at $5 and $25.
Is Claude Opus 4.8 or Claude Sonnet 5.5 better for coding?
Claude Sonnet 5.5 scores higher on coding benchmarks: 67.3 versus 59.9 in the Noometry coding category.
Which has the bigger context window?
Both accept 1M tokens.
How many benchmarks do Claude Opus 4.8 and Claude Sonnet 5.5 share?
29 benchmarks have published results for both models. Claude Opus 4.8 has 65 scored results on Noometry and Claude Sonnet 5.5 has 32.