Claude Sonnet 4.5 vs Kimi K3
Claude Sonnet 4.5 (Anthropic) and Kimi K3 (Moonshot) compared on benchmarks, pricing, context window, and use-case rankings.
- Kimi K3 leads on overall intelligence (ECI 158 vs 147).
- Kimi K3 is cheaper on input tokens — $2.10 vs $3.00 per 1M.
- Kimi K3 has a larger context window (1M vs 1M tokens).
- Kimi K3 ranks higher for coding (97th vs 26th percentile).
| Attribute | Claude Sonnet 4.5 | Kimi K3 |
|---|---|---|
| Scores | ||
| Intelligence (ECI) | 147 | 158 |
| Coding | 26 | 97 |
| Math | 41 | 82 |
| Reasoning & Knowledge | 23 | 73 |
| Agentic & Tools | 17 | 80 |
| Specifications | ||
| Developer | Anthropic | Moonshot |
| Family | Claude | Kimi |
| Released | Sep 29, 2025 | Jul 16, 2026 |
| Parameters | — | 2.8T |
| Availability | API access | Open weights (non-commercial) |
| Context window | 1M | 1M |
| Price — $/M input | $3.00 | $2.10 |
| Price — $/M output | $15.00 | $10.95 |
| Inputs | text, image, file | text, image, video |
| Outputs | text | text |
| Benchmarks | ||
| AIME 2024/2025 | 78% | 97% |
| ARC-AGI | 64% | 95% |
| ARC-AGI-2 | 14% | 60% |
| FrontierMath | 15% | — |
| FrontierMath Tier 4 | 4% | — |
| GDPval (win/tie rate) | 50% | — |
| GPQA Diamond | 82% | 93% |
| GSO (code optimization) | 15% | — |
| Humanity's Last Exam | 14% | 47% |
| MATH Level 5 | 98% | — |
| METR task horizon | 2.0 h | — |
| SimpleBench | 54% | 61% |
| SimpleQA Verified | 31% | 51% |
| SWE-bench Verified | 71% | — |
| Terminal-Bench | 47% | — |
| WebDev Arena | 1391 | 1674 |
| WeirdML | 48% | 83% |
| APEX | — | 39% |
| SciCode | — | 60% |
Use-case scores are 0–100 percentile composites across each area’s benchmarks, ranked against every model from the past year. Highlighted cells lead each row. Open a model for the full picture.
Frequently asked questions
Is Claude Sonnet 4.5 better than Kimi K3?
On Epoch AI's Capabilities Index, Kimi K3 scores higher (158) than Claude Sonnet 4.5 (147). The right pick depends on your task — compare their coding, math, and reasoning scores in the table above.
Which is cheaper, Claude Sonnet 4.5 or Kimi K3?
Kimi K3 is cheaper on input tokens at $2.10 per million, versus $3.00 (representative OpenRouter pricing).
Which has a larger context window, Claude Sonnet 4.5 or Kimi K3?
Kimi K3 supports up to 1M tokens, compared with 1M for the other.
Which is better for coding, Claude Sonnet 4.5 or Kimi K3?
Across coding benchmarks like SWE-bench Verified and Terminal-Bench, Kimi K3 ranks higher — 97th vs 26th percentile among the models tracked on Model Beat.
Want a different match-up? Open the compare tool to add or swap models.
More comparisons
Benchmarks & model data from Epoch AI (CC BY); pricing & specs from OpenRouter. ECI = Epoch Capabilities Index.