Model comparison
Claude Opus 5.5 vs o3-pro
Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 42.9 on the Noometry Index.
Last verified . 5 shared benchmarks.
Summary
- They share 5 benchmarks with published results for both. Claude Opus 5.5 scores higher in 4 categories and o3-pro in 1 category; 5 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where Claude Opus 5.5 leads 80.2 to 23.8.
- The biggest single-benchmark swing is ARC-AGI-2: 93.3% for Claude Opus 5.5 and 4.9% for o3-pro.
- Claude Opus 5.5 is cheaper at $4 / $20 per million input/output tokens, against $20 / $80 for o3-pro.
- Claude Opus 5.5 accepts more context: 1M tokens versus 200K.
Side by side
| Claude Opus 5.5 | o3-pro | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 68.6 | 42.9 |
| Released | 2026-09-22 | 2025-06-10 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 200K |
| Max output | 128K | 100K |
| Input $ / M tokens | $4 | $20 |
| Output $ / M tokens | $20 | $80 |
| Results tracked | 44 | 12 |
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Category by category
Coding Claude Opus 5.5 leads
Claude Opus 5.5: 71.9 (#3), o3-pro: 55.5 (#24)
| Benchmark | Claude Opus 5.5 | o3-pro |
|---|---|---|
| FrontierCode | 54.6% | — |
| Aider Polyglot | — | 84.9% |
| CursorBench | 57.8% | — |
| LMArena WebDev | 1813 | — |
| FrontierSWE | 62.3% | — |
| SciCode | 66.9% | — |
| WeirdML | — | 58.2% |
| LMArena Coding | 1547 | — |
| MirrorCode | 77.4% | — |
| ALE-Bench | 2,147 | — |
Agentic & Tool Use Not comparable
Claude Opus 5.5: 45.3 (#15), o3-pro: —
| Benchmark | Claude Opus 5.5 | o3-pro |
|---|---|---|
| APEX-Agents | 73.5% | — |
| GDP.pdf | 30.6% | — |
| Vending-Bench 2 | 9,235 | — |
Reasoning Claude Opus 5.5 leads
Claude Opus 5.5: 80.2 (#3), o3-pro: 23.8 (#171)
| Benchmark | Claude Opus 5.5 | o3-pro |
|---|---|---|
| ARC-AGI-2 | 93.3% | 4.9% |
| ARC-AGI-1 | 98.5% | 59.3% |
| DTBench | 98.9% | 86.9% |
| LMCA | 68.2% | 38.5% |
| Epoch Capabilities Index | 167.33 | 147.42 |
| Kagi LLM Benchmark | — | 72.1% |
| NYT Connections (extended) | 88.5% | — |
| CritPt | 31.7% | — |
| EBR-Bench | 71.4% | — |
| LMArena Hard Prompts | 1535 | — |
| Mystery Game Puzzles | 71% | — |
Math Not comparable
Claude Opus 5.5: 91.8 (#3), o3-pro: —
| Benchmark | Claude Opus 5.5 | o3-pro |
|---|---|---|
| FrontierMath (Tiers 1-3) | 91.2% | — |
| FrontierMath Tier 4 | 95% | — |
| OTIS Mock AIME 2024-2025 | 100% | — |
| ProofBench | 100% | — |
| LMArena Math | 1506 | — |
| FrontierMath Erdős | 2.9% | — |
Knowledge Claude Opus 5.5 leads
Claude Opus 5.5: 66.4 (#10), o3-pro: 29.5 (#238)
| Benchmark | Claude Opus 5.5 | o3-pro |
|---|---|---|
| GPQA Diamond | 90.6% | — |
| SimpleQA Verified | 72.2% | — |
| Confabulations | — | 14.2% |
| Vectara Hallucination Rate | — | 23.3% |
| LMArena Expert | 1547 | — |
Multimodal Not comparable
Claude Opus 5.5: 57.8 (#1), o3-pro: —
| Benchmark | Claude Opus 5.5 | o3-pro |
|---|---|---|
| LMArena Vision | 1321 | — |
| Blueprint-Bench 2 | 51.2% | — |
| Furniture Assembly | 83.3% | — |
Multilingual Not comparable
Claude Opus 5.5: 59.1 (#2), o3-pro: —
| Benchmark | Claude Opus 5.5 | o3-pro |
|---|---|---|
| LMArena Non-English | 1507 | — |
| LMArena Chinese | 1588 | — |
| LMArena French | 1514 | — |
| LMArena Russian | 1520 | — |
| LMArena Spanish | 1507 | — |
Instruction Following Not comparable
Claude Opus 5.5: 80.0 (#3), o3-pro: —
| Benchmark | Claude Opus 5.5 | o3-pro |
|---|---|---|
| LMArena Instruction Following | 1537 | — |
Long Context o3-pro leads
Claude Opus 5.5: 47.1 (#19), o3-pro: 72.2 (#1)
| Benchmark | Claude Opus 5.5 | o3-pro |
|---|---|---|
| Fiction.LiveBench | — | 97.2% |
| LMArena Longer Query | 1532 | — |
Writing & Preference Claude Opus 5.5 leads
Claude Opus 5.5: 78.2 (#3), o3-pro: 57.1 (#133)
| Benchmark | Claude Opus 5.5 | o3-pro |
|---|---|---|
| LMArena Text | 1515 | — |
| LMArena Creative Writing | 1533 | — |
| Short-Story Creative Writing | — | 84.4% |
| EQ-Bench Creative Writing | 2050 | — |
| LMArena Multi-Turn | 1499 | — |
Frequently asked questions
Is Claude Opus 5.5 better than o3-pro?
Claude Opus 5.5 is the stronger model overall, scoring 68.6 to 42.9 on the Noometry Index.
Which is cheaper, Claude Opus 5.5 or o3-pro?
Claude Opus 5.5 is cheaper. It lists at $4 per million input tokens and $20 per million output tokens; o3-pro lists at $20 and $80.
Is Claude Opus 5.5 or o3-pro better for coding?
Claude Opus 5.5 scores higher on coding benchmarks: 71.9 versus 55.5 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 o3-pro share?
5 benchmarks have published results for both models. Claude Opus 5.5 has 44 scored results on Noometry and o3-pro has 12.