Model comparison
Claude Opus 5 vs Claude Sonnet 5.5
Claude Opus 5 is the stronger model overall, scoring 67.7 to 60.5 on the Noometry Index. Claude Sonnet 5.5 costs 2.5× less per token, which makes it the better buy when Claude Opus 5's lead doesn't matter for your workload.
Last verified . 16 shared benchmarks.
Summary
- They share 16 benchmarks with published results for both. Claude Opus 5 scores higher in 4 categories and Claude Sonnet 5.5 in 2 categories; 5 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Claude Opus 5 leads 77.1 to 52.4.
- The biggest single-benchmark swing is Furniture Assembly: 60.8% for Claude Opus 5 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 5.
Side by side
| Claude Opus 5 | Claude Sonnet 5.5 | |
|---|---|---|
| Provider | Anthropic | Anthropic |
| Noometry Index | 67.7 | 60.5 |
| Released | 2026-07-24 | 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 | 57 | 16 |
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Category by category
Coding Claude Opus 5 leads
Claude Opus 5: 67.0 (#5), Claude Sonnet 5.5: 65.5 (#6)
| Benchmark | Claude Opus 5 | Claude Sonnet 5.5 |
|---|---|---|
| FrontierCode | 53.4% | 52.1% |
| CursorBench | 46.6% | 55.5% |
| LMArena WebDev | 1694 | 1699 |
| FrontierSWE | 52% | 61.9% |
| SciCode | 56.4% | 61% |
| ALE-Bench | 2,165 | 1,819 |
| DeepSWE | 73.6% | — |
| WeirdML | 91.8% | — |
| LMArena Coding | 1533 | — |
Agentic & Tool Use Claude Opus 5 leads
Claude Opus 5: 55.5 (#1), Claude Sonnet 5.5: 44.9 (#14)
| Benchmark | Claude Opus 5 | Claude Sonnet 5.5 |
|---|---|---|
| APEX-Agents | 65.8% | 75.5% |
| OSWorld 2.0 | 31.4% | — |
| τ²-bench Banking | 48.7% | — |
| PostTrainBench | 35% | — |
| BALROG | 63.4% | — |
| GBAEval | 79.6% | — |
| GDP.pdf | 24% | — |
| Vending-Bench 2 | 11,182 | — |
Reasoning Claude Opus 5 leads
Claude Opus 5: 77.1 (#3), Claude Sonnet 5.5: 52.4 (#29)
| Benchmark | Claude Opus 5 | Claude Sonnet 5.5 |
|---|---|---|
| CritPt | 29.1% | 31.4% |
| Mystery Game Puzzles | 59% | 65% |
| ARC-AGI-2 | 90.4% | — |
| SimpleBench | 80.6% | — |
| NYT Connections (extended) | 94.3% | — |
| ARC-AGI-1 | 97.5% | — |
| Chess Puzzles | 42% | — |
| EBR-Bench | 45.7% | — |
| LMArena Hard Prompts | 1525 | — |
| DTBench | 97.9% | — |
| LMCA | 64.5% | — |
| Bench to the Future 3 | 0.12 | — |
| Epoch Capabilities Index | 162.67 | — |
Math Claude Sonnet 5.5 leads
Claude Opus 5: 86.1 (#6), Claude Sonnet 5.5: 88.7 (#4)
| Benchmark | Claude Opus 5 | Claude Sonnet 5.5 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 85.6% | 88.8% |
| FrontierMath Tier 4 | 73.2% | 80.5% |
| OTIS Mock AIME 2024-2025 | 98.9% | 100% |
| ProofBench | 99% | 100% |
| LMArena Math | 1533 | — |
Knowledge Too close to call
Claude Opus 5: 66.8 (#8), Claude Sonnet 5.5: 66.0 (#11)
| Benchmark | Claude Opus 5 | Claude Sonnet 5.5 |
|---|---|---|
| GPQA Diamond | 93.9% | 95.6% |
| SimpleQA Verified | 59.9% | 46.5% |
| LMArena Expert | 1558 | — |
Multimodal Claude Sonnet 5.5 leads
Claude Opus 5: 51.1 (#6), Claude Sonnet 5.5: 53.2 (#5)
| Benchmark | Claude Opus 5 | Claude Sonnet 5.5 |
|---|---|---|
| Furniture Assembly | 60.8% | 75% |
| LMArena Vision | 1321 | — |
| Blueprint-Bench 2 | 30.4% | — |
| LMArena Document | 1516 | — |
Multilingual Not comparable
Claude Opus 5: 58.8 (#3), Claude Sonnet 5.5: —
| Benchmark | Claude Opus 5 | Claude Sonnet 5.5 |
|---|---|---|
| LMArena Non-English | 1500 | — |
| LMArena Chinese | 1575 | — |
| LMArena French | 1522 | — |
| LMArena German | 1522 | — |
| LMArena Japanese | 1510 | — |
| LMArena Korean | 1526 | — |
| LMArena Russian | 1507 | — |
| LMArena Spanish | 1519 | — |
Instruction Following Not comparable
Claude Opus 5: 79.3 (#5), Claude Sonnet 5.5: —
| Benchmark | Claude Opus 5 | Claude Sonnet 5.5 |
|---|---|---|
| LMArena Instruction Following | 1516 | — |
Long Context Not comparable
Claude Opus 5: 46.5 (#20), Claude Sonnet 5.5: —
| Benchmark | Claude Opus 5 | Claude Sonnet 5.5 |
|---|---|---|
| LMArena Longer Query | 1516 | — |
Writing & Preference Not comparable
Claude Opus 5: 79.3 (#2), Claude Sonnet 5.5: —
| Benchmark | Claude Opus 5 | Claude Sonnet 5.5 |
|---|---|---|
| LMArena Text | 1506 | — |
| LMArena Creative Writing | 1491 | — |
| EQ-Bench Creative Writing | 2133 | — |
| EQ-Bench 4 | 1385 | — |
| LMArena Multi-Turn | 1496 | — |
Frequently asked questions
Is Claude Opus 5 better than Claude Sonnet 5.5?
Claude Opus 5 is the stronger model overall, scoring 67.7 to 60.5 on the Noometry Index. Claude Sonnet 5.5 costs 2.5× less per token, which makes it the better buy when Claude Opus 5's lead doesn't matter for your workload.
Which is cheaper, Claude Opus 5 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 5 lists at $5 and $25.
Is Claude Opus 5 or Claude Sonnet 5.5 better for coding?
Claude Opus 5 scores higher on coding benchmarks: 67.0 versus 65.5 in the Noometry coding category.
Which has the bigger context window?
Both accept 1M tokens.
How many benchmarks do Claude Opus 5 and Claude Sonnet 5.5 share?
16 benchmarks have published results for both models. Claude Opus 5 has 57 scored results on Noometry and Claude Sonnet 5.5 has 16.