Model comparison
Claude Opus 5.5 vs o1
Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 40.9 on the Noometry Index.
Last verified . 23 shared benchmarks.
Summary
- They share 23 benchmarks with published results for both. Claude Opus 5.5 scores higher in 9 categories and o1 in 1 category; 10 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Opus 5.5 leads 91.8 to 36.1.
- The biggest single-benchmark swing is FrontierMath (Tiers 1-3): 91.2% for Claude Opus 5.5 and 14.7% for o1.
- Claude Opus 5.5 is cheaper at $4 / $20 per million input/output tokens, against $15 / $60 for o1.
- Claude Opus 5.5 accepts more context: 1M tokens versus 200K.
Side by side
| Claude Opus 5.5 | o1 | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 68.6 | 40.9 |
| Released | 2026-09-22 | 2024-09-12 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 200K |
| Max output | 128K | 100K |
| Input $ / M tokens | $4 | $15 |
| Output $ / M tokens | $20 | $60 |
| Results tracked | 44 | 52 |
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Category by category
Coding Claude Opus 5.5 leads
Claude Opus 5.5: 71.9 (#3), o1: 46.1 (#70)
| Benchmark | Claude Opus 5.5 | o1 |
|---|---|---|
| LMArena Coding | 1547 | 1367 |
| FrontierCode | 54.6% | — |
| Aider Polyglot | — | 61.7% |
| CursorBench | 57.8% | — |
| LMArena WebDev | 1813 | — |
| FrontierSWE | 62.3% | — |
| SciCode | 66.9% | — |
| WeirdML | — | 47.6% |
| LiveBench Coding | — | 69.7% |
| MirrorCode | 77.4% | — |
| CadEval | — | 56% |
| ALE-Bench | 2,147 | — |
| HumanEval+ | — | 89% |
| MBPP+ | — | 80.2% |
Agentic & Tool Use Claude Opus 5.5 leads
Claude Opus 5.5: 45.3 (#15), o1: 24.6 (#117)
| Benchmark | Claude Opus 5.5 | o1 |
|---|---|---|
| APEX-Agents | 73.5% | — |
| Cybench | — | 10% |
| GDP.pdf | 30.6% | — |
| METR Time Horizons | — | 51.1% |
| Vending-Bench 2 | 9,235 | — |
Reasoning Claude Opus 5.5 leads
Claude Opus 5.5: 80.2 (#3), o1: 27.9 (#111)
| Benchmark | Claude Opus 5.5 | o1 |
|---|---|---|
| ARC-AGI-1 | 98.5% | 30.7% |
| LMArena Hard Prompts | 1535 | 1371 |
| DTBench | 98.9% | 74.7% |
| LMCA | 68.2% | 22.3% |
| Epoch Capabilities Index | 167.33 | 141.91 |
| ARC-AGI-2 | 93.3% | — |
| SimpleBench | — | 41.7% |
| NYT Connections (extended) | 88.5% | — |
| CritPt | 31.7% | — |
| Chess Puzzles | — | 15% |
| EnigmaEval | — | 5.7% |
| EBR-Bench | 71.4% | — |
| LiveBench Reasoning | — | 91.6% |
| Mystery Game Puzzles | 71% | — |
| LiveBench Data Analysis | — | 65.5% |
| LiveBench | — | 75.7% |
Math Claude Opus 5.5 leads
Claude Opus 5.5: 91.8 (#3), o1: 36.1 (#175)
| Benchmark | Claude Opus 5.5 | o1 |
|---|---|---|
| FrontierMath (Tiers 1-3) | 91.2% | 14.7% |
| OTIS Mock AIME 2024-2025 | 100% | 73.3% |
| LMArena Math | 1506 | 1388 |
| FrontierMath Tier 4 | 95% | — |
| ProofBench | 100% | — |
| LiveBench Math | — | 80.3% |
| MATH Level 5 | — | 94.7% |
| FrontierMath (Feb 2025 set) | — | 9.3% |
| FrontierMath Erdős | 2.9% | — |
Knowledge Claude Opus 5.5 leads
Claude Opus 5.5: 66.4 (#10), o1: 41.5 (#110)
| Benchmark | Claude Opus 5.5 | o1 |
|---|---|---|
| GPQA Diamond | 90.6% | 76.8% |
| SimpleQA Verified | 72.2% | 41.1% |
| LMArena Expert | 1547 | 1361 |
| Humanity's Last Exam | — | 8% |
| Confabulations | — | 11.7% |
Multimodal Claude Opus 5.5 leads
Claude Opus 5.5: 57.8 (#1), o1: 34.2 (#93)
| Benchmark | Claude Opus 5.5 | o1 |
|---|---|---|
| LMArena Vision | 1321 | 1168 |
| GeoBench | — | 80% |
| VPCT | — | 37% |
| Blueprint-Bench 2 | 51.2% | — |
| Furniture Assembly | 83.3% | — |
| SpatialViz-Bench | — | 41.4% |
Multilingual Claude Opus 5.5 leads
Claude Opus 5.5: 59.1 (#2), o1: 48.6 (#142)
| Benchmark | Claude Opus 5.5 | o1 |
|---|---|---|
| LMArena Non-English | 1507 | 1358 |
| LMArena Chinese | 1588 | 1394 |
| LMArena French | 1514 | 1344 |
| LMArena Russian | 1520 | 1356 |
| LMArena Spanish | 1507 | 1345 |
| LMArena German | — | 1337 |
| LMArena Japanese | — | 1346 |
| LMArena Korean | — | 1396 |
Instruction Following Claude Opus 5.5 leads
Claude Opus 5.5: 80.0 (#3), o1: 74.8 (#86)
| Benchmark | Claude Opus 5.5 | o1 |
|---|---|---|
| LMArena Instruction Following | 1537 | 1367 |
| LiveBench Instruction Following | — | 81.5% |
Long Context o1 leads
Claude Opus 5.5: 47.1 (#19), o1: 50.3 (#9)
| Benchmark | Claude Opus 5.5 | o1 |
|---|---|---|
| LMArena Longer Query | 1532 | 1378 |
| Fiction.LiveBench | — | 83.3% |
Writing & Preference Claude Opus 5.5 leads
Claude Opus 5.5: 78.2 (#3), o1: 55.6 (#144)
| Benchmark | Claude Opus 5.5 | o1 |
|---|---|---|
| LMArena Text | 1515 | 1366 |
| LMArena Creative Writing | 1533 | 1348 |
| LMArena Multi-Turn | 1499 | 1369 |
| Short-Story Creative Writing | — | 70.2% |
| EQ-Bench Creative Writing | 2050 | — |
| LiveBench Language | — | 65.4% |
Frequently asked questions
Is Claude Opus 5.5 better than o1?
Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 40.9 on the Noometry Index.
Which is cheaper, Claude Opus 5.5 or o1?
Claude Opus 5.5 is cheaper. It lists at $4 per million input tokens and $20 per million output tokens; o1 lists at $15 and $60.
Is Claude Opus 5.5 or o1 better for coding?
Claude Opus 5.5 scores higher on coding benchmarks: 71.9 versus 46.1 in the Noometry coding category.
Which has the bigger context window?
Claude Opus 5.5 does, with 1M tokens against 200K.
How many benchmarks do Claude Opus 5.5 and o1 share?
23 benchmarks have published results for both models. Claude Opus 5.5 has 44 scored results on Noometry and o1 has 52.