Comparing 2 models
Claude Opus 5.5 vs GPT-6 Astra
Benchmarks through
Verdict
Claude Opus 5.5 places higher on 15 of the 20 tasks where both are ranked. Claude Opus 5.5 costs 2.5x less per input token. GPT-6 Astra accepts 1.1x more context.
- Choose Claude Opus 5.5 for OpenClaw (#1), Coding (#1), Frontend & UI (#1).
- Choose GPT-6 Astra for Logic & Problem Solving (#4), Tool & Function Calling (#4), RAG & Long Context (#4).
Built from the published task rankings below; ranks come from each task's own weighted benchmarks, so a win on one task says nothing about another.
Measured head to head
Benchmarks both models were run on
| Evaluation | Claude Opus 5.5 | GPT-6 Astra | Source |
|---|---|---|---|
| FACTS Grounding | 68.5% | 82% | source · 2026-09-24 |
| FrontierMath Tiers 1-3 (Epoch AI) | 91.2% ± 1.7 | 93.7% ± 1.4 | source · 2026-09-22 |
| GPQA Diamond (Epoch AI) | 90.6% ± 1.9 | 95.8% ± 1.4 | source · 2026-09-22 |
| LiveBench Agentic Coding | 71.7% | 57.3% | source · 2026-10-16 |
| LiveBench Coding | 89.3% | 80.4% | source · 2026-10-16 |
| LiveBench Data Analysis | 80.3% | 83.0% | source · 2026-10-16 |
| LiveBench Instruction Following | 65.7% | 75.6% | source · 2026-10-16 |
| LiveBench Language | 86.3% | 89.4% | source · 2026-10-16 |
| LiveBench Math | 97.1% | 96.8% | source · 2026-10-16 |
| LiveBench Reasoning | 92.2% | 92.7% | source · 2026-10-16 |
| LMArena Agent | 17.2 | 13.7 | source · 2026-10-14 |
| LMArena Agent Bash Recovery | 13.6 | 5.5 | source · 2026-10-08 |
| LMArena Agent Steerability | 17.9 | 14.6 | source · 2026-10-14 |
| LMArena Agent Task Outcome | 19.4 | 12.5 | source · 2026-10-14 |
| LMArena Agent Tool Hallucination | 0.5 | 0.6 | source · 2026-10-14 |
| LMArena Creative Writing | 1534 Elo | 1421 Elo | source · 2026-10-15 |
| LMArena Instruction Following | 1536 Elo | 1455 Elo | source · 2026-10-15 |
| LMArena Long Query | 1531 Elo | 1461 Elo | source · 2026-10-15 |
| LMArena Math | 1508 Elo | 1465 Elo | source · 2026-10-15 |
| LMArena Search Factuality | 1205 Elo | 1240 Elo | source · 2026-10-13 |
| LMArena Text | 1508 Elo | 1477 Elo | source · 2026-10-15 |
| LMArena Text Factuality | 1509 Elo | 1466 Elo | source · 2026-10-15 |
| LMArena Vision | 1293 Elo | 1286 Elo | source · 2026-10-09 |
| LMArena Vision Diagrams | 1324 Elo | 1311 Elo | source · 2026-10-09 |
| LMArena Vision OCR | 1307 Elo | 1302 Elo | source · 2026-10-09 |
| LMArena WebDev | 1811 Elo | 1780 Elo | source · 2026-10-13 |
| LMArena WebDev Image-to-Web | 1749 Elo | 1731 Elo | source · 2026-10-09 |
| OTIS Mock AIME (Epoch AI) | 100% ± 0 | 100% ± 0 | source · 2026-09-22 |
| SimpleQA Verified (Epoch AI) | 72.2% ± 1.4 | 75.6% ± 1.4 | source · 2026-09-22 |
| Terminal-Bench (4.0) | 64.8% | 58.2% | source · 2026-10-16 |
Values are as published by each evaluator, in its own units; rows from different evaluators are not on a common scale.
task evidence
How they place when the question changes
Lower ranks are better. “Best” marks the strongest option in this shortlist for that task.