Comparing 2 models
Claude Sonnet 5.5 vs Kimi K3
Benchmarks through
Verdict
Claude Sonnet 5.5 places higher on 5 of the 5 tasks where both are ranked. Kimi K3 costs 6.6x less per input token. Kimi K3 accepts 1.0x more context. Only Kimi K3 has open weights for self-hosting.
- Choose Claude Sonnet 5.5 for Debugging & Code Review (#1), Code Completion (#1), Autonomous Agents (#2).
- Choose Kimi K3 for 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 Sonnet 5.5 | Kimi K3 | Source |
|---|---|---|---|
| Design Arena Coding | 1366 Elo | 1363 Elo | source · 2026-10-16 |
| Design Arena UI | 1378 Elo | 1346 Elo | source · 2026-10-16 |
| Design Arena Website | 1330 Elo | 1337 Elo | source · 2026-10-16 |
| FrontierMath Tiers 1-3 (Epoch AI) | 88.8% ± 1.9 | 72.2% ± 2.7 | source · 2026-09-29 |
| GPQA Diamond (Epoch AI) | 95.6% ± 1.4 | 93.1% ± 1.5 | source · 2026-09-29 |
| LiveBench Agentic Coding | 56.3% | 62.2% | source · 2026-10-16 |
| LiveBench Coding | 91.4% | 81.5% | source · 2026-10-16 |
| LiveBench Data Analysis | 59.5% | 78.7% | source · 2026-10-16 |
| LiveBench Instruction Following | 56.8% | 71.4% | source · 2026-10-16 |
| LiveBench Language | 78.0% | 85.5% | source · 2026-10-16 |
| LiveBench Math | 96.1% | 84.4% | source · 2026-10-16 |
| LiveBench Reasoning | 91.6% | 90.7% | source · 2026-10-16 |
| LMArena Agent | 12.5 | 1.9 | source · 2026-10-14 |
| LMArena Agent Bash Recovery | 15 | 4.4 | source · 2026-10-08 |
| LMArena Agent Steerability | 12.3 | 0.5 | source · 2026-10-14 |
| LMArena Agent Task Outcome | 20 | 6.3 | source · 2026-10-14 |
| LMArena Agent Tool Hallucination | 0.5 | 0.6 | source · 2026-10-14 |
| LMArena Creative Writing | 1467 Elo | 1456 Elo | source · 2026-10-15 |
| LMArena Instruction Following | 1488 Elo | 1483 Elo | source · 2026-10-15 |
| LMArena Long Query | 1494 Elo | 1493 Elo | source · 2026-10-15 |
| LMArena Math | 1499 Elo | 1494 Elo | source · 2026-10-15 |
| LMArena Text | 1475 Elo | 1487 Elo | source · 2026-10-15 |
| LMArena Text Factuality | 1474 Elo | 1471 Elo | source · 2026-10-15 |
| LMArena WebDev | 1774 Elo | 1655 Elo | source · 2026-10-13 |
| LMArena WebDev Image-to-Web | 1740 Elo | 1579 Elo | source · 2026-10-09 |
| OTIS Mock AIME (Epoch AI) | 100% ± 0 | 97.2% ± 1.1 | source · 2026-09-29 |
| SimpleQA Verified (Epoch AI) | 46.5% ± 1.6 | 50.6% ± 1.6 | source · 2026-09-29 |
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.