Model comparison
Claude Sonnet 4.5 vs GPT-5.1
GPT-5.1 is the stronger model overall, scoring 48.8 to 44.0 on the Noometry Index.
Last verified . 53 shared benchmarks.
Summary
- They share 53 benchmarks with published results for both. Claude Sonnet 4.5 scores higher in 3 categories and GPT-5.1 in 7 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in math, where GPT-5.1 leads 50.3 to 31.9.
- The biggest single-benchmark swing is MMLU-Pro: 86.9% for Claude Sonnet 4.5 and 57.9% for GPT-5.1.
- GPT-5.1 is cheaper at $1.25 / $10 per million input/output tokens, against $3 / $15 for Claude Sonnet 4.5.
- Claude Sonnet 4.5 accepts more context: 1M tokens versus 400K.
Side by side
| Claude Sonnet 4.5 | GPT-5.1 | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 44.0 | 48.8 |
| Released | 2025-09-29 | 2025-11-13 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 400K |
| Max output | 64K | 128K |
| Input $ / M tokens | $3 | $1.25 |
| Output $ / M tokens | $15 | $10 |
| Results tracked | 73 | 63 |
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Category by category
Coding Too close to call
Claude Sonnet 4.5: 47.8 (#54), GPT-5.1: 46.9 (#59)
| Benchmark | Claude Sonnet 4.5 | GPT-5.1 |
|---|---|---|
| SWE-bench Verified | 71.3% | 68% |
| SWE-bench Verified (bash only) | 71.4% | 66% |
| LMArena WebDev | 1393 | 1395 |
| SciCode | 44.7% | 43.3% |
| GSO | 14.7% | 13.7% |
| WeirdML | 47.7% | 60.8% |
| LMArena Coding | 1489 | 1454 |
| ALE-Bench | 796.15 | 1,192 |
| SWE-bench Multilingual | 67% | — |
| LiveBench Coding | — | 72.5% |
| AlgoTune | 1.52 | — |
Agentic & Tool Use Claude Sonnet 4.5 leads
Claude Sonnet 4.5: 38.1 (#30), GPT-5.1: 32.5 (#55)
| Benchmark | Claude Sonnet 4.5 | GPT-5.1 |
|---|---|---|
| Terminal-Bench | 46.5% | 47.6% |
| DeepResearch Bench | 52.6% | 42.8% |
| LMArena Search | 1159 | 1199 |
| Vending-Bench 2 | 3,839 | 1,473 |
| Berkeley Function Calling Leaderboard | 73.2% | — |
| GDPval | 42.5% | — |
| Remote Labor Index | 2.1% | — |
| τ²-bench Airline | 72% | — |
| τ²-bench Banking | 25.3% | — |
| τ²-bench Retail | 72.4% | — |
| τ²-bench Telecom | 84.9% | — |
| Cybench | 60% | — |
| OSWorld | 62.9% | — |
| METR Time Horizons | 67.4% | — |
Reasoning GPT-5.1 leads
Claude Sonnet 4.5: 26.9 (#113), GPT-5.1: 39.9 (#50)
| Benchmark | Claude Sonnet 4.5 | GPT-5.1 |
|---|---|---|
| ARC-AGI-2 | 13.6% | 17.6% |
| SimpleBench | 54.3% | 53.2% |
| ARC-AGI-1 | 63.7% | 72.8% |
| CritPt | 1.1% | 4.9% |
| Chess Puzzles | 12% | 32% |
| EnigmaEval | 6% | 11.2% |
| LMArena Hard Prompts | 1462 | 1457 |
| Mystery Game Puzzles | 17% | 19% |
| DTBench | 83.2% | 90.1% |
| LMCA | 38.8% | 43.9% |
| Epoch Capabilities Index | 146.84 | 149.66 |
| ForecastBench | 61.9 | 58.1 |
| Kagi LLM Benchmark | 57.9% | — |
| NYT Connections (extended) | 37.3% | — |
| EBR-Bench | 2.4% | — |
| LiveBench Reasoning | — | 95.8% |
| LiveBench Data Analysis | — | 72.1% |
| LiveBench | — | 78.8% |
Math GPT-5.1 leads
Claude Sonnet 4.5: 31.9 (#190), GPT-5.1: 50.3 (#45)
| Benchmark | Claude Sonnet 4.5 | GPT-5.1 |
|---|---|---|
| OTIS Mock AIME 2024-2025 | 77.8% | 88.6% |
| Omni-MATH | 55.3% | 46.4% |
| LMArena Math | 1448 | 1446 |
| FrontierMath (Feb 2025 set) | 15.2% | 31% |
| FrontierMath Tier 4 (v1) | 4.2% | 12.5% |
| FrontierMath (Tiers 1-3) | 23.9% | — |
| FrontierMath Tier 4 | 2.4% | — |
| ProofBench | 19% | — |
| LiveBench Math | — | 94.5% |
| MATH Level 5 | 97.7% | — |
Knowledge GPT-5.1 leads
Claude Sonnet 4.5: 48.4 (#70), GPT-5.1: 50.5 (#65)
| Benchmark | Claude Sonnet 4.5 | GPT-5.1 |
|---|---|---|
| GPQA Diamond | 82.3% | 87.6% |
| Humanity's Last Exam | 13.7% | 23.7% |
| SimpleQA Verified | 30.7% | 48% |
| MMLU-Pro | 86.9% | 57.9% |
| Vectara Hallucination Rate | 12% | 10.9% |
| GPQA (HELM) | 68.6% | 44.2% |
| LMArena Expert | 1483 | 1470 |
Multimodal GPT-5.1 leads
Claude Sonnet 4.5: 34.1 (#84), GPT-5.1: 44.0 (#17)
| Benchmark | Claude Sonnet 4.5 | GPT-5.1 |
|---|---|---|
| VPCT | 39.8% | 58.7% |
| LMArena Document | 1450 | 1403 |
| LMArena Vision | — | 1250 |
Multilingual Too close to call
Claude Sonnet 4.5: 53.6 (#65), GPT-5.1: 54.0 (#51)
| Benchmark | Claude Sonnet 4.5 | GPT-5.1 |
|---|---|---|
| LMArena Non-English | 1425 | 1431 |
| LMArena Chinese | 1459 | 1495 |
| LMArena French | 1459 | 1451 |
| LMArena German | 1427 | 1439 |
| LMArena Japanese | 1390 | 1453 |
| LMArena Korean | 1403 | 1401 |
| LMArena Russian | 1436 | 1435 |
| LMArena Spanish | 1457 | 1430 |
Instruction Following GPT-5.1 leads
Claude Sonnet 4.5: 75.2 (#74), GPT-5.1: 84.0 (#1)
| Benchmark | Claude Sonnet 4.5 | GPT-5.1 |
|---|---|---|
| IFEval | 85% | 93.5% |
| LMArena Instruction Following | 1459 | 1442 |
| LiveBench Instruction Following | — | 93.3% |
Long Context GPT-5.1 leads
Claude Sonnet 4.5: 45.2 (#45), GPT-5.1: 47.6 (#14)
| Benchmark | Claude Sonnet 4.5 | GPT-5.1 |
|---|---|---|
| LMArena Longer Query | 1476 | 1448 |
| CL-bench | — | 23.7% |
| CL-bench Life | — | 17.3% |
Writing & Preference Claude Sonnet 4.5 leads
Claude Sonnet 4.5: 66.7 (#33), GPT-5.1: 64.7 (#53)
| Benchmark | Claude Sonnet 4.5 | GPT-5.1 |
|---|---|---|
| LMArena Text | 1439 | 1443 |
| LMArena Creative Writing | 1442 | 1427 |
| WildBench | 85.4% | 86.3% |
| LMArena Multi-Turn | 1465 | 1449 |
| EQ-Bench Creative Writing | 1678 | — |
| LiveBench Language | — | 80.2% |
Frequently asked questions
Is Claude Sonnet 4.5 better than GPT-5.1?
GPT-5.1 is the stronger model overall, scoring 48.8 to 44.0 on the Noometry Index.
Which is cheaper, Claude Sonnet 4.5 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 4.5 lists at $3 and $15.
Is Claude Sonnet 4.5 or GPT-5.1 better for coding?
They score almost the same on coding (47.8 vs 46.9); test both on your own repository before choosing.
Which has the bigger context window?
Claude Sonnet 4.5 does, with 1M tokens against 400K.
How many benchmarks do Claude Sonnet 4.5 and GPT-5.1 share?
53 benchmarks have published results for both models. Claude Sonnet 4.5 has 73 scored results on Noometry and GPT-5.1 has 63.