Model comparison
Claude Sonnet 5.5 vs o3-pro
Claude Sonnet 5.5 is the stronger model overall, scoring 60.5 to 42.7 on the Noometry Index.
Last verified . 0 shared benchmarks.
Summary
- The widest gap is in knowledge, where Claude Sonnet 5.5 leads 66.0 to 29.0.
- Claude Sonnet 5.5 is cheaper at $2 / $10 per million input/output tokens, against $20 / $80 for o3-pro.
- Claude Sonnet 5.5 accepts more context: 1M tokens versus 200K.
Side by side
| Claude Sonnet 5.5 | o3-pro | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 60.5 | 42.7 |
| Released | 2026-09-28 | 2025-06-10 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 200K |
| Max output | 128K | 100K |
| Input $ / M tokens | $2 | $20 |
| Output $ / M tokens | $10 | $80 |
| Results tracked | 16 | 12 |
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Category by category
Coding Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 65.5 (#6), o3-pro: 55.1 (#22)
| Benchmark | Claude Sonnet 5.5 | o3-pro |
|---|---|---|
| FrontierCode | 52.1% | — |
| Aider Polyglot | — | 84.9% |
| CursorBench | 55.5% | — |
| LMArena WebDev | 1699 | — |
| FrontierSWE | 61.9% | — |
| SciCode | 61% | — |
| WeirdML | — | 58.2% |
| ALE-Bench | 1,819 | — |
Agentic & Tool Use Not comparable
Claude Sonnet 5.5: 44.9 (#14), o3-pro: —
| Benchmark | Claude Sonnet 5.5 | o3-pro |
|---|---|---|
| APEX-Agents | 75.5% | — |
Reasoning Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 52.4 (#29), o3-pro: 24.1 (#152)
| Benchmark | Claude Sonnet 5.5 | o3-pro |
|---|---|---|
| ARC-AGI-2 | — | 4.9% |
| Kagi LLM Benchmark | — | 72.1% |
| ARC-AGI-1 | — | 59.3% |
| CritPt | 31.4% | — |
| Mystery Game Puzzles | 65% | — |
| DTBench | — | 86.9% |
| LMCA | — | 38.5% |
| Epoch Capabilities Index | — | 147.43 |
Math Not comparable
Claude Sonnet 5.5: 88.7 (#4), o3-pro: —
| Benchmark | Claude Sonnet 5.5 | o3-pro |
|---|---|---|
| FrontierMath (Tiers 1-3) | 88.8% | — |
| FrontierMath Tier 4 | 80.5% | — |
| OTIS Mock AIME 2024-2025 | 100% | — |
| ProofBench | 100% | — |
Knowledge Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 66.0 (#11), o3-pro: 29.0 (#234)
| Benchmark | Claude Sonnet 5.5 | o3-pro |
|---|---|---|
| GPQA Diamond | 95.6% | — |
| SimpleQA Verified | 46.5% | — |
| Confabulations | — | 14.2% |
| Vectara Hallucination Rate | — | 23.3% |
Multimodal Not comparable
Claude Sonnet 5.5: 53.2 (#5), o3-pro: —
| Benchmark | Claude Sonnet 5.5 | o3-pro |
|---|---|---|
| Furniture Assembly | 75% | — |
Long Context Not comparable
Claude Sonnet 5.5: —, o3-pro: 72.1 (#1)
| Benchmark | Claude Sonnet 5.5 | o3-pro |
|---|---|---|
| Fiction.LiveBench | — | 97.2% |
Writing & Preference Not comparable
Claude Sonnet 5.5: —, o3-pro: 57.1 (#128)
| Benchmark | Claude Sonnet 5.5 | o3-pro |
|---|---|---|
| Short-Story Creative Writing | — | 84.4% |
Frequently asked questions
Is Claude Sonnet 5.5 better than o3-pro?
Claude Sonnet 5.5 is the stronger model overall, scoring 60.5 to 42.7 on the Noometry Index.
Which is cheaper, Claude Sonnet 5.5 or o3-pro?
Claude Sonnet 5.5 is cheaper. It lists at $2 per million input tokens and $10 per million output tokens; o3-pro lists at $20 and $80.
Is Claude Sonnet 5.5 or o3-pro better for coding?
Claude Sonnet 5.5 scores higher on coding benchmarks: 65.5 versus 55.1 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 5.5 and o3-pro share?
0 benchmarks have published results for both models. Claude Sonnet 5.5 has 16 scored results on Noometry and o3-pro has 12.