Model comparison
Claude Sonnet 5.5 vs GPT-5.1
Claude Sonnet 5.5 is the stronger model overall, scoring 60.5 to 48.8 on the Noometry Index.
Last verified . 8 shared benchmarks.
Summary
- They share 8 benchmarks with published results for both. Claude Sonnet 5.5 scores higher in 6 categories and GPT-5.1 in 0 categories; 6 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Sonnet 5.5 leads 88.7 to 50.3.
- The biggest single-benchmark swing is Mystery Game Puzzles: 65% for Claude Sonnet 5.5 and 19% for GPT-5.1.
- GPT-5.1 is cheaper at $1.25 / $10 per million input/output tokens, against $2 / $10 for Claude Sonnet 5.5.
- Claude Sonnet 5.5 accepts more context: 1M tokens versus 400K.
Side by side
| Claude Sonnet 5.5 | GPT-5.1 | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 60.5 | 48.8 |
| Released | 2026-09-28 | 2025-11-13 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 400K |
| Max output | 128K | 128K |
| Input $ / M tokens | $2 | $1.25 |
| Output $ / M tokens | $10 | $10 |
| Results tracked | 16 | 63 |
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Category by category
Coding Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 65.5 (#6), GPT-5.1: 46.9 (#59)
| Benchmark | Claude Sonnet 5.5 | GPT-5.1 |
|---|---|---|
| LMArena WebDev | 1699 | 1395 |
| SciCode | 61% | 43.3% |
| ALE-Bench | 1,819 | 1,192 |
| SWE-bench Verified | — | 68% |
| FrontierCode | 52.1% | — |
| SWE-bench Verified (bash only) | — | 66% |
| CursorBench | 55.5% | — |
| FrontierSWE | 61.9% | — |
| GSO | — | 13.7% |
| WeirdML | — | 60.8% |
| LiveBench Coding | — | 72.5% |
| LMArena Coding | — | 1454 |
Agentic & Tool Use Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 44.9 (#14), GPT-5.1: 32.5 (#55)
| Benchmark | Claude Sonnet 5.5 | GPT-5.1 |
|---|---|---|
| Terminal-Bench | — | 47.6% |
| APEX-Agents | 75.5% | — |
| DeepResearch Bench | — | 42.8% |
| LMArena Search | — | 1199 |
| Vending-Bench 2 | — | 1,473 |
Reasoning Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 52.4 (#29), GPT-5.1: 39.9 (#50)
| Benchmark | Claude Sonnet 5.5 | GPT-5.1 |
|---|---|---|
| CritPt | 31.4% | 4.9% |
| Mystery Game Puzzles | 65% | 19% |
| ARC-AGI-2 | — | 17.6% |
| SimpleBench | — | 53.2% |
| ARC-AGI-1 | — | 72.8% |
| Chess Puzzles | — | 32% |
| EnigmaEval | — | 11.2% |
| LiveBench Reasoning | — | 95.8% |
| LMArena Hard Prompts | — | 1457 |
| DTBench | — | 90.1% |
| LiveBench Data Analysis | — | 72.1% |
| LMCA | — | 43.9% |
| Epoch Capabilities Index | — | 149.66 |
| ForecastBench | — | 58.1 |
| LiveBench | — | 78.8% |
Math Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 88.7 (#4), GPT-5.1: 50.3 (#45)
| Benchmark | Claude Sonnet 5.5 | GPT-5.1 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 100% | 88.6% |
| FrontierMath (Tiers 1-3) | 88.8% | — |
| FrontierMath Tier 4 | 80.5% | — |
| ProofBench | 100% | — |
| Omni-MATH | — | 46.4% |
| LiveBench Math | — | 94.5% |
| LMArena Math | — | 1446 |
| FrontierMath (Feb 2025 set) | — | 31% |
| FrontierMath Tier 4 (v1) | — | 12.5% |
Knowledge Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 66.0 (#11), GPT-5.1: 50.5 (#65)
| Benchmark | Claude Sonnet 5.5 | GPT-5.1 |
|---|---|---|
| GPQA Diamond | 95.6% | 87.6% |
| SimpleQA Verified | 46.5% | 48% |
| Humanity's Last Exam | — | 23.7% |
| MMLU-Pro | — | 57.9% |
| Vectara Hallucination Rate | — | 10.9% |
| GPQA (HELM) | — | 44.2% |
| LMArena Expert | — | 1470 |
Multimodal Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 53.2 (#5), GPT-5.1: 44.0 (#17)
| Benchmark | Claude Sonnet 5.5 | GPT-5.1 |
|---|---|---|
| LMArena Vision | — | 1250 |
| VPCT | — | 58.7% |
| Furniture Assembly | 75% | — |
| LMArena Document | — | 1403 |
Multilingual Not comparable
Claude Sonnet 5.5: —, GPT-5.1: 54.0 (#51)
| Benchmark | Claude Sonnet 5.5 | GPT-5.1 |
|---|---|---|
| LMArena Non-English | — | 1431 |
| LMArena Chinese | — | 1495 |
| LMArena French | — | 1451 |
| LMArena German | — | 1439 |
| LMArena Japanese | — | 1453 |
| LMArena Korean | — | 1401 |
| LMArena Russian | — | 1435 |
| LMArena Spanish | — | 1430 |
Instruction Following Not comparable
Claude Sonnet 5.5: —, GPT-5.1: 84.0 (#1)
| Benchmark | Claude Sonnet 5.5 | GPT-5.1 |
|---|---|---|
| LiveBench Instruction Following | — | 93.3% |
| IFEval | — | 93.5% |
| LMArena Instruction Following | — | 1442 |
Long Context Not comparable
Claude Sonnet 5.5: —, GPT-5.1: 47.6 (#14)
| Benchmark | Claude Sonnet 5.5 | GPT-5.1 |
|---|---|---|
| CL-bench | — | 23.7% |
| CL-bench Life | — | 17.3% |
| LMArena Longer Query | — | 1448 |
Writing & Preference Not comparable
Claude Sonnet 5.5: —, GPT-5.1: 64.7 (#53)
| Benchmark | Claude Sonnet 5.5 | GPT-5.1 |
|---|---|---|
| LMArena Text | — | 1443 |
| LMArena Creative Writing | — | 1427 |
| WildBench | — | 86.3% |
| LMArena Multi-Turn | — | 1449 |
| LiveBench Language | — | 80.2% |
Frequently asked questions
Is Claude Sonnet 5.5 better than GPT-5.1?
Claude Sonnet 5.5 is the stronger model overall, scoring 60.5 to 48.8 on the Noometry Index.
Which is cheaper, Claude Sonnet 5.5 or GPT-5.1?
GPT-5.1 is cheaper. It lists at $1.25 per million input tokens and $10 per million output tokens; Claude Sonnet 5.5 lists at $2 and $10.
Is Claude Sonnet 5.5 or GPT-5.1 better for coding?
Claude Sonnet 5.5 scores higher on coding benchmarks: 65.5 versus 46.9 in the Noometry coding category.
Which has the bigger context window?
Claude Sonnet 5.5 does, with 1M tokens against 400K.
How many benchmarks do Claude Sonnet 5.5 and GPT-5.1 share?
8 benchmarks have published results for both models. Claude Sonnet 5.5 has 16 scored results on Noometry and GPT-5.1 has 63.