Model comparison
Claude Sonnet 5.5 vs GPT-6.1 Sol
GPT-6.1 Sol is the stronger model overall, scoring 65.6 to 61.9 on the Noometry Index.
Last verified . 28 shared benchmarks.
Summary
- They share 28 benchmarks with published results for both. Claude Sonnet 5.5 scores higher in 6 categories and GPT-6.1 Sol in 4 categories; 10 gaps are clear of the uncertainty.
- The widest gap is in reasoning, where GPT-6.1 Sol leads 81.9 to 54.0.
- The biggest single-benchmark swing is SimpleQA Verified: 46.5% for Claude Sonnet 5.5 and 73.9% for GPT-6.1 Sol.
- Both cost about the same: $2 input and $10 output per million tokens.
- GPT-6.1 Sol accepts more context: 1.05M tokens versus 1M.
Side by side
| Claude Sonnet 5.5 | GPT-6.1 Sol | |
|---|---|---|
| Provider | Anthropic | OpenAI |
| Noometry Index | 61.9 | 65.6 |
| Released | 2026-09-28 | 2026-09-29 |
| Weights | Proprietary | Proprietary |
| Context window | 1M | 1.05M |
| Max output | 128K | 128K |
| Input $ / M tokens | $2 | $2 |
| Output $ / M tokens | $10 | $10 |
| Results tracked | 32 | 34 |
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Category by category
Coding Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 67.3 (#6), GPT-6.1 Sol: 63.2 (#8)
| Benchmark | Claude Sonnet 5.5 | GPT-6.1 Sol |
|---|---|---|
| FrontierCode | 52.1% | 50.2% |
| LMArena WebDev | 1774 | 1755 |
| SciCode | 61% | 55.8% |
| LMArena Coding | 1513 | 1487 |
| DeepSWE | — | 75.2% |
| CursorBench | 55.5% | — |
| FrontierSWE | 61.9% | — |
| ALE-Bench | 1,819 | — |
Agentic & Tool Use Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 45.0 (#16), GPT-6.1 Sol: 39.6 (#26)
| Benchmark | Claude Sonnet 5.5 | GPT-6.1 Sol |
|---|---|---|
| APEX-Agents | 75.5% | 60% |
| GDP.pdf | — | 32% |
Reasoning GPT-6.1 Sol leads
Claude Sonnet 5.5: 54.0 (#28), GPT-6.1 Sol: 81.9 (#2)
| Benchmark | Claude Sonnet 5.5 | GPT-6.1 Sol |
|---|---|---|
| NYT Connections (extended) | 80.5% | 95.5% |
| CritPt | 31.4% | 31.7% |
| LMArena Hard Prompts | 1495 | 1466 |
| Mystery Game Puzzles | 65% | 80% |
| Epoch Capabilities Index | 165.03 | 166.09 |
| ARC-AGI-2 | — | 94.2% |
| ARC-AGI-1 | — | 98.5% |
| Chess Puzzles | — | 61% |
| EBR-Bench | — | 54.3% |
Math GPT-6.1 Sol leads
Claude Sonnet 5.5: 87.9 (#6), GPT-6.1 Sol: 93.7 (#1)
| Benchmark | Claude Sonnet 5.5 | GPT-6.1 Sol |
|---|---|---|
| FrontierMath (Tiers 1-3) | 88.8% | 93.7% |
| FrontierMath Tier 4 | 80.5% | 100% |
| OTIS Mock AIME 2024-2025 | 100% | 100% |
| ProofBench | 100% | 99% |
| LMArena Math | 1510 | 1464 |
| FrontierMath Erdős | 2.9% | — |
Knowledge GPT-6.1 Sol leads
Claude Sonnet 5.5: 66.0 (#12), GPT-6.1 Sol: 71.8 (#4)
| Benchmark | Claude Sonnet 5.5 | GPT-6.1 Sol |
|---|---|---|
| GPQA Diamond | 95.6% | 95.4% |
| SimpleQA Verified | 46.5% | 73.9% |
| LMArena Expert | 1540 | 1502 |
Multimodal GPT-6.1 Sol leads
Claude Sonnet 5.5: 51.5 (#6), GPT-6.1 Sol: 52.7 (#5)
| Benchmark | Claude Sonnet 5.5 | GPT-6.1 Sol |
|---|---|---|
| LMArena Vision | 1289 | 1288 |
| Furniture Assembly | 75% | 80% |
Multilingual Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 55.3 (#30), GPT-6.1 Sol: 54.3 (#46)
| Benchmark | Claude Sonnet 5.5 | GPT-6.1 Sol |
|---|---|---|
| LMArena Non-English | 1452 | 1438 |
| LMArena Chinese | 1522 | 1477 |
| LMArena Russian | 1451 | 1455 |
Instruction Following Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 78.3 (#11), GPT-6.1 Sol: 77.0 (#29)
| Benchmark | Claude Sonnet 5.5 | GPT-6.1 Sol |
|---|---|---|
| LMArena Instruction Following | 1495 | 1468 |
Long Context Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 45.9 (#28), GPT-6.1 Sol: 44.9 (#54)
| Benchmark | Claude Sonnet 5.5 | GPT-6.1 Sol |
|---|---|---|
| LMArena Longer Query | 1498 | 1465 |
Writing & Preference Claude Sonnet 5.5 leads
Claude Sonnet 5.5: 66.0 (#40), GPT-6.1 Sol: 63.6 (#63)
| Benchmark | Claude Sonnet 5.5 | GPT-6.1 Sol |
|---|---|---|
| LMArena Text | 1471 | 1447 |
| LMArena Creative Writing | 1465 | 1432 |
| LMArena Multi-Turn | 1474 | 1449 |
Frequently asked questions
Is Claude Sonnet 5.5 better than GPT-6.1 Sol?
GPT-6.1 Sol is the stronger model overall, scoring 65.6 to 61.9 on the Noometry Index.
Which is cheaper, Claude Sonnet 5.5 or GPT-6.1 Sol?
GPT-6.1 Sol is cheaper. It lists at $2 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-6.1 Sol better for coding?
Claude Sonnet 5.5 scores higher on coding benchmarks: 67.3 versus 63.2 in the Noometry coding category.
Which has the bigger context window?
GPT-6.1 Sol does, with 1.05M tokens against 1M.
How many benchmarks do Claude Sonnet 5.5 and GPT-6.1 Sol share?
28 benchmarks have published results for both models. Claude Sonnet 5.5 has 32 scored results on Noometry and GPT-6.1 Sol has 34.