Comparing 2 models
Claude Opus 5.5 vs Kimi K3
Benchmarks through
Verdict
Claude Opus 5.5 places higher on 6 of the 8 tasks where both are ranked. Kimi K3 costs 13.2x less per input token. Kimi K3 accepts 1.0x more context. Only Kimi K3 has open weights for self-hosting.
- Choose Claude Opus 5.5 for Agentic Coding (#1), Autonomous Agents (#1), AI Agents (#1).
- Choose Kimi K3 for JSON & Schema Output (#4), Structured Data Extraction (#4), you need to self-host.
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 | Kimi K3 | Source |
|---|---|---|---|
| Design Arena Coding | 1392 Elo | 1363 Elo | source · 2026-10-16 |
| Design Arena UI | 1378 Elo | 1346 Elo | source · 2026-10-16 |
| Design Arena Website | 1338 Elo | 1337 Elo | source · 2026-10-16 |
| FrontierMath Tiers 1-3 (Epoch AI) | 91.2% ± 1.7 | 72.2% ± 2.7 | source · 2026-09-22 |
| GPQA Diamond (Epoch AI) | 90.6% ± 1.9 | 93.1% ± 1.5 | source · 2026-09-22 |
| LiveBench Agentic Coding | 71.7% | 62.2% | source · 2026-10-16 |
| LiveBench Coding | 89.3% | 81.5% | source · 2026-10-16 |
| LiveBench Data Analysis | 80.3% | 78.7% | source · 2026-10-16 |
| LiveBench Instruction Following | 65.7% | 71.4% | source · 2026-10-16 |
| LiveBench Language | 86.3% | 85.5% | source · 2026-10-16 |
| LiveBench Math | 97.1% | 84.4% | source · 2026-10-16 |
| LiveBench Reasoning | 92.2% | 90.7% | source · 2026-10-16 |
| LMArena Agent | 17.2 | 1.9 | source · 2026-10-14 |
| LMArena Agent Bash Recovery | 13.6 | 4.4 | source · 2026-10-08 |
| LMArena Agent Steerability | 17.9 | 0.5 | source · 2026-10-14 |
| LMArena Agent Task Outcome | 19.4 | 6.3 | source · 2026-10-14 |
| LMArena Agent Tool Hallucination | 0.5 | 0.6 | source · 2026-10-14 |
| LMArena Creative Writing | 1534 Elo | 1456 Elo | source · 2026-10-15 |
| LMArena Instruction Following | 1536 Elo | 1483 Elo | source · 2026-10-15 |
| LMArena Long Query | 1531 Elo | 1493 Elo | source · 2026-10-15 |
| LMArena Math | 1508 Elo | 1494 Elo | source · 2026-10-15 |
| LMArena Text | 1508 Elo | 1487 Elo | source · 2026-10-15 |
| LMArena Text Factuality | 1509 Elo | 1471 Elo | source · 2026-10-15 |
| LMArena WebDev | 1811 Elo | 1655 Elo | source · 2026-10-13 |
| LMArena WebDev Image-to-Web | 1749 Elo | 1579 Elo | source · 2026-10-09 |
| OTIS Mock AIME (Epoch AI) | 100% ± 0 | 97.2% ± 1.1 | source · 2026-09-22 |
| SimpleQA Verified (Epoch AI) | 72.2% ± 1.4 | 50.6% ± 1.6 | source · 2026-09-22 |
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.