GPT-5.5 Pro vs GPT-5.6 Sol
GPT-5.5 Pro Verdict
- GPT-5.6 Sol (max) leads on quality: 68.8 vs 67.1.
- GPT-5.5 Pro (xhigh) is stronger in maths, reasoning.
- GPT-5.6 Sol (max) is stronger in agents & tools, coding, composite, instruction following, knowledge, long context, multimodal.
- GPT-5.6 Sol (max) is 8.4× cheaper ($8.00 vs $67.50 per 1M blended).
- GPT-5.6 Sol (max) streams 15.2× faster (61 vs 4 tokens per second).
| Metric | GPT-5.5 Pro (xhigh) | GPT-5.6 Sol (max) |
|---|---|---|
| BenchLeader Index | 67.1 | 68.8 |
| Maths score | 74.5 | 74.3 |
| Reasoning score | 80.1 | 73.7 |
| Agents & tools score | – | 66.6 |
| Coding score | – | 67.0 |
| Composite score | – | 79.2 |
| Instruction following score | – | 71.0 |
| Knowledge score | – | 66.5 |
| Long context score | – | 68.5 |
| Multimodal score | – | 68.1 |
| Blended price $/M | $67.50 | $8.00 |
| Output speed | 4 tok/s | 61 tok/s |
| Time to first answer | 3.5 s | 127.3 s |
| Context window | 1.1M | 1.1M |
| GPQA Diamond | – | 93.5% |
| FrontierMath Tiers 1–3 | 87.7% | 89.1% |
| FrontierMath Tier 4 | 78.0% | 82.9% |
| OTIS Mock AIME | – | 100.0% |
| SimpleQA Verified | – | 69.7% |
| Terminal-Bench | – | 37.3% |
| OSWorld-Verified 2.0 | – | 27.3% |
| SciCode | – | 56.1% |
| WeirdML | – | 87.0% |
| APEX-Agents | – | 39.9% |
| ProofBench | – | 83.0% |
| LiveBench | – | 81.0% |
| LiveBench Reasoning | – | 91.7% |
| LiveBench Coding | – | 83.9% |
| LiveBench Agentic Coding | – | 56.2% |
| LiveBench Mathematics | – | 96.2% |
| LiveBench Data Analysis | – | 79.8% |
| LiveBench Language | – | 87.7% |
| LiveBench Instruction Following | – | 71.8% |
| AA Intelligence Index | – | 47.1 |
| IFBench | – | 72.7% |
| AA-LCR | – | 84.0% |
| MMMU-Pro | – | 83.4% |
| AA-Omniscience | – | 22.0 |
| Terminal-Bench Hard | – | 65.9% |
| GPQA Diamond (AA) | – | 94.1% |
| Humanity's Last Exam (AA) | – | 49.5% |
| SciCode (AA) | – | 57.1% |
| τ²-Bench Telecom (AA) | – | 85.1% |
| LiveCodeBench | – | 82.6% |
| MMLU-Pro | – | 89.1% |
| IOI | – | 91.2% |
| LegalBench | – | 87.0% |
| CorpFin | – | 64.4% |
| TaxEval | – | 74.8% |
| Terminal-Bench 2.1 (Vals) | – | 85.8% |
| SWE-bench (Vals) | – | 96.2% |
| GPQA Diamond (Vals) | – | 95.2% |
| Vals Index | – | 63.7 |
| PRBench Finance | – | 50.5% |
| PRBench Legal | – | 50.5% |
| ARC-AGI-1 | 95.0% | 96.5% |
| ARC-AGI-2 | 84.2% | 92.5% |
| ARC-AGI-3 | – | 7.8% |
| CritPt | 30.6% | 32.3% |
| GDPval (AA) | – | 54.3% |
| τ²-Bench Banking (AA) | – | 44.3% |
| ITBench SRE (AA) | – | 56.2% |
| Analyst Agent (AA) | – | 47.5% |
| BioMysteryBench | – | 71.1% |
| Code Migration | – | 52.9% |
| CUA-bench | – | 8.3% |
| Excel Modeling Benchmark | – | 72.3% |
| Finance Agent v2 | – | 53.8% |
| Harvey's Legal Agent Benchmark | – | 2.5% |
| Legal Research Bench | – | 48.1% |
| MedCode | – | 44.0% |
| MedScribe | – | 85.2% |
| MMMU-Pro (Vals) | – | 88.8% |
| MortgageTax | – | 67.3% |
| MysteryMechanism | – | 33.3% |
| ProgramBench | – | 1.5% |
| Public Benefits Bench | – | 66.5% |
| SAGE | – | 52.6% |
| SkillsBench | – | 54.1% |
| SREBench | – | 30.5% |
| Tax Agent Bench | – | 68.0% |
| Terminal-Bench 4.0 (Vals) | – | 27.8% |
| Terminal-Bench Science | – | 12.9% |
| Time Horizon Index: KSP | – | 23.8% |
| Vals Multimodal Index | – | 72.6% |
| Vibe Code Bench 1-100 | – | 20.0% |
| Vibe Code Bench v1.1 | – | 80.5% |
| Web Search Index | – | 43.6% |
| DrugDiscoveryBench | – | 56.5% |
| Chess Puzzles | – | 55.0% |
| EBR-bench | – | 44.8% |
| Mystery Game Puzzles | – | 58.0% |
| PostTrainBench | – | 36.2% |
| DeepSWE | – | 72.7% |
| LMCA | 53.9% | 58.4% |
| DTBench | 96.0% | 95.5% |
| CursorBench | – | 67.2% |
| ALE-Bench | – | 2176.9 |
| GDP.pdf | – | 30.7% |
| FrontierSWE | – | 32.2% |
| BTF-3 | – | 13.7% |
Data as of 2026-09-19. Best configuration of each model; every score links to its source on the model pages.
GPT-5.5 Pro vs GPT-5.6 Sol: questions
- Is GPT-5.5 Pro better than GPT-5.6 Sol?
- GPT-5.6 Sol (max) leads on quality: 68.8 vs 67.1. The BenchLeader Index combines every independent quality benchmark; GPT-5.6 Sol (max) is ahead overall as of 2026-09-19, but check the category scores for your use.
- Which is cheaper, GPT-5.5 Pro or GPT-5.6 Sol?
- GPT-5.6 Sol is cheaper: $8.00 against $67.50 per million tokens, blended at three input tokens per output token.
- Which is faster, GPT-5.5 Pro or GPT-5.6 Sol?
- GPT-5.6 Sol streams faster: 61 against 4 output tokens per second.
- Which has the larger context window?
- Both accept 1.1M tokens of context.