Model comparison
GPT-5.5 Pro vs GPT-6.1 Sol
GPT-6.1 Sol is the stronger model overall, scoring 65.6 to 64.3 on the Noometry Index.
Last verified . 9 shared benchmarks.
Summary
- They share 9 benchmarks with published results for both. GPT-5.5 Pro scores higher in 0 categories and GPT-6.1 Sol in 3 categories; 3 gaps are clear of the uncertainty.
- The widest gap is in math, where GPT-6.1 Sol leads 93.7 to 84.0.
- The biggest single-benchmark swing is FrontierMath Tier 4: 78% for GPT-5.5 Pro and 100% for GPT-6.1 Sol.
- GPT-6.1 Sol is cheaper at $2 / $10 per million input/output tokens, against $30 / $180 for GPT-5.5 Pro.
Side by side
| GPT-5.5 Pro | GPT-6.1 Sol | |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Noometry Index | 64.3 | 65.6 |
| Released | 2026-04-23 | 2026-09-29 |
| Weights | Proprietary | Proprietary |
| Context window | 1.05M | 1.05M |
| Max output | 128K | 128K |
| Input $ / M tokens | $30 | $2 |
| Output $ / M tokens | $180 | $10 |
| Results tracked | 14 | 34 |
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Category by category
Coding Not comparable
GPT-5.5 Pro: —, GPT-6.1 Sol: 63.2 (#8)
| Benchmark | GPT-5.5 Pro | GPT-6.1 Sol |
|---|---|---|
| DeepSWE | — | 75.2% |
| FrontierCode | — | 50.2% |
| LMArena WebDev | — | 1755 |
| SciCode | — | 55.8% |
| LMArena Coding | — | 1487 |
Agentic & Tool Use Not comparable
GPT-5.5 Pro: —, GPT-6.1 Sol: 39.6 (#26)
| Benchmark | GPT-5.5 Pro | GPT-6.1 Sol |
|---|---|---|
| APEX-Agents | — | 60% |
| GDP.pdf | — | 32% |
Reasoning GPT-6.1 Sol leads
GPT-5.5 Pro: 73.3 (#10), GPT-6.1 Sol: 81.9 (#2)
| Benchmark | GPT-5.5 Pro | GPT-6.1 Sol |
|---|---|---|
| ARC-AGI-2 | 84.6% | 94.2% |
| ARC-AGI-1 | 96.5% | 98.5% |
| CritPt | 30.6% | 31.7% |
| Chess Puzzles | 64% | 61% |
| Epoch Capabilities Index | 162.07 | 166.09 |
| SimpleBench | 76.9% | — |
| NYT Connections (extended) | — | 95.5% |
| EBR-Bench | — | 54.3% |
| LMArena Hard Prompts | — | 1466 |
| Mystery Game Puzzles | — | 80% |
| DTBench | 96% | — |
| LMCA | 53.9% | — |
Math GPT-6.1 Sol leads
GPT-5.5 Pro: 84.0 (#10), GPT-6.1 Sol: 93.7 (#1)
| Benchmark | GPT-5.5 Pro | GPT-6.1 Sol |
|---|---|---|
| FrontierMath (Tiers 1-3) | 87.7% | 93.7% |
| FrontierMath Tier 4 | 78% | 100% |
| OTIS Mock AIME 2024-2025 | 100% | 100% |
| ProofBench | — | 99% |
| LMArena Math | — | 1464 |
| FrontierMath (Feb 2025 set) | 52.4% | — |
| FrontierMath Tier 4 (v1) | 39.6% | — |
Knowledge GPT-6.1 Sol leads
GPT-5.5 Pro: 64.1 (#19), GPT-6.1 Sol: 71.8 (#4)
| Benchmark | GPT-5.5 Pro | GPT-6.1 Sol |
|---|---|---|
| GPQA Diamond | 93.9% | 95.4% |
| SimpleQA Verified | — | 73.9% |
| LMArena Expert | — | 1502 |
Multimodal Not comparable
GPT-5.5 Pro: —, GPT-6.1 Sol: 52.7 (#5)
| Benchmark | GPT-5.5 Pro | GPT-6.1 Sol |
|---|---|---|
| LMArena Vision | — | 1288 |
| Furniture Assembly | — | 80% |
Multilingual Not comparable
GPT-5.5 Pro: —, GPT-6.1 Sol: 54.3 (#46)
| Benchmark | GPT-5.5 Pro | GPT-6.1 Sol |
|---|---|---|
| LMArena Non-English | — | 1438 |
| LMArena Chinese | — | 1477 |
| LMArena Russian | — | 1455 |
Instruction Following Not comparable
GPT-5.5 Pro: —, GPT-6.1 Sol: 77.0 (#29)
| Benchmark | GPT-5.5 Pro | GPT-6.1 Sol |
|---|---|---|
| LMArena Instruction Following | — | 1468 |
Long Context Not comparable
GPT-5.5 Pro: —, GPT-6.1 Sol: 44.9 (#54)
| Benchmark | GPT-5.5 Pro | GPT-6.1 Sol |
|---|---|---|
| LMArena Longer Query | — | 1465 |
Writing & Preference Not comparable
GPT-5.5 Pro: —, GPT-6.1 Sol: 63.6 (#63)
| Benchmark | GPT-5.5 Pro | GPT-6.1 Sol |
|---|---|---|
| LMArena Text | — | 1447 |
| LMArena Creative Writing | — | 1432 |
| LMArena Multi-Turn | — | 1449 |
Frequently asked questions
Is GPT-5.5 Pro better than GPT-6.1 Sol?
GPT-6.1 Sol is the stronger model overall, scoring 65.6 to 64.3 on the Noometry Index.
Which is cheaper, GPT-5.5 Pro 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; GPT-5.5 Pro lists at $30 and $180.
Which has the bigger context window?
Both accept 1.05M tokens.
How many benchmarks do GPT-5.5 Pro and GPT-6.1 Sol share?
9 benchmarks have published results for both models. GPT-5.5 Pro has 14 scored results on Noometry and GPT-6.1 Sol has 34.