Claude Sonnet 5 vs Kimi K3: Benchmark Comparison
Claude Sonnet 5 has the higher score on 5 of 27 shared benchmarks; Kimi K3 leads on 22.
The largest observed score gap is 28.29 pts on Code Migration , where Claude Sonnet 5 leads.
Reported ±1 standard-error ranges overlap on 12 of 27 shared benchmarks with comparable uncertainty data. This is not a pairwise statistical significance test.
Shared benchmark results
Scores and reported standard errors come from the latest visible Vals benchmark version available for both models.
| Benchmark | Claude Sonnet 5 | Kimi K3 | Gap | Reported uncertainty |
|---|---|---|---|---|
| Vals Index | 51.77% ±1.09 | 50.30% ±0.99 | 1.48 pts | Reported ±1 SE ranges overlap |
| Harvey's Legal Agent Benchmark | 5.00% ±1.65 | 12.92% ±2.68 | 7.92 pts | Reported ±1 SE ranges do not overlap |
| Legal Research Bench | 41.83% ±3.43 | 46.15% ±3.46 | 4.33 pts | Reported ±1 SE ranges overlap |
| LegalBench | 83.92% ±0.46 | 86.21% ±0.41 | 2.29 pts | Reported ±1 SE ranges do not overlap |
| EMB | 66.32% ±3.01 | 66.68% ±2.87 | 0.36 pts | Reported ±1 SE ranges overlap |
| Finance Agent (v2) | 53.91% ±0.52 | 53.11% ±0.37 | 0.80 pts | Reported ±1 SE ranges overlap |
| MortgageTax | 70.03% ±0.90 | 66.34% ±0.91 | 3.70 pts | Reported ±1 SE ranges do not overlap |
| Tax Agent Bench | 62.27% ±3.19 | 68.67% ±3.08 | 6.40 pts | Reported ±1 SE ranges do not overlap |
| TaxEval v2 | 75.63% ±0.84 | 75.72% ±0.84 | 0.08 pts | Reported ±1 SE ranges overlap |
| MedCode | 47.54% ±2.27 | 49.36% ±2.20 | 1.82 pts | Reported ±1 SE ranges overlap |
| MedScribe | 76.05% ±3.05 | 88.05% ±1.98 | 11.99 pts | Reported ±1 SE ranges do not overlap |
| ProofBench v1.1 | 77.00% ±4.23 | 87.00% ±3.38 | 10.00 pts | Reported ±1 SE ranges do not overlap |
| Terminal-Bench Science | 5.71% ±2.79 | 1.43% ±1.43 | 4.29 pts | Reported ±1 SE ranges do not overlap |
| GPQA Diamond | 88.89% ±2.22 | 92.93% ±1.31 | 4.04 pts | Reported ±1 SE ranges do not overlap |
| MMLU Pro | 87.55% ±0.37 | 87.97% ±0.32 | 0.43 pts | Reported ±1 SE ranges overlap |
| MMMU Pro | 83.01% ±0.90 | 88.15% ±0.78 | 5.14 pts | Reported ±1 SE ranges do not overlap |
| SAGE | 48.92% ±3.40 | 52.78% ±3.41 | 3.86 pts | Reported ±1 SE ranges overlap |
| Code Migration | 44.39% ±4.25 | 16.10% ±4.10 | 28.29 pts | Reported ±1 SE ranges do not overlap |
| IOI | 45.00% ±2.75 | 48.94% ±9.82 | 3.94 pts | Reported ±1 SE ranges overlap |
| LiveCodeBench | 82.43% ±1.09 | 87.19% ±0.97 | 4.76 pts | Reported ±1 SE ranges do not overlap |
| ProgramBench | 0.00% ±0.00 | 2.00% ±0.99 | 2.00 pts | Reported ±1 SE ranges do not overlap |
| SWE-bench | 79.60% ±1.80 | 93.40% ±1.11 | 13.80 pts | Reported ±1 SE ranges do not overlap |
| Terminal-Bench 4.0 | 9.60% ±1.01 | 17.17% ±0.51 | 7.58 pts | Reported ±1 SE ranges do not overlap |
| Vibe Code Bench 1-100 | 13.82% ±2.98 | 18.24% ±3.92 | 4.42 pts | Reported ±1 SE ranges overlap |
| Vibe Code Bench v1.1 | 81.33% ±3.05 | 84.97% ±2.75 | 3.64 pts | Reported ±1 SE ranges overlap |
| CyberBench v1.1 | 61.91% ±5.74 | 75.24% ±5.56 | 13.33 pts | Reported ±1 SE ranges do not overlap |
| Public Benefits Bench v1.1 | 66.03% ±1.23 | 68.20% ±1.21 | 2.17 pts | Reported ±1 SE ranges overlap |
Performance by category
| Category | Claude Sonnet 5 average | Kimi K3 average |
|---|---|---|
| Legal | 43.58% | 48.43% |
| Finance | 65.63% | 66.10% |
| Healthcare | 61.80% | 68.70% |
| Math | 77.00% | 87.00% |
| Science | 5.71% | 1.43% |
| Academic | 86.48% | 89.68% |
| Education | 48.92% | 52.78% |
| Coding | 44.52% | 46.00% |
| Cyber | 61.91% | 75.24% |
| Social Mobility | 66.03% | 68.20% |
Cost and latency
Cost per test appears only where the benchmark reports it for both models. Latency is the measured completion time for that benchmark.
| Benchmark | Claude Sonnet 5 cost | Kimi K3 cost | Claude Sonnet 5 latency | Kimi K3 latency |
|---|---|---|---|---|
| Vals Index | $13.72 | $6.38 | 54m16s | 1h08m |
| Harvey's Legal Agent Benchmark | $8.95 | $3.83 | 38m52s | 13m58s |
| Legal Research Bench | $2.72 | $3.47 | 25m46s | 12m40s |
| LegalBench | N/A | N/A | 4.90s | 7.11s |
| EMB | $10.29 | $3.07 | 49m46s | 12m21s |
| Finance Agent (v2) | $0.75 | $1.91 | 13m12s | 4m46s |
| MortgageTax | N/A | N/A | 28.67s | 78.94s |
| Tax Agent Bench | $1.79 | $2.79 | 19m19s | 40m15s |
| TaxEval v2 | N/A | N/A | 3m22s | 2m25s |
| MedCode | N/A | N/A | 2m15s | 36.99s |
| MedScribe | N/A | N/A | 4m12s | 38.24s |
| ProofBench v1.1 | $1.37 | $1.65 | 14m58s | 34m31s |
| Terminal-Bench Science | $28.28 | $21.30 | 2h59m | 4h49m |
| GPQA Diamond | N/A | N/A | 63.23s | 2m02s |
| MMLU Pro | N/A | N/A | 25.19s | 38.72s |
| MMMU Pro | N/A | N/A | 18.82s | 106.52s |
| SAGE | N/A | N/A | 7m14s | 47.30s |
| Code Migration | $35.31 | $13.87 | 1h57m | 4h18m |
| IOI | $12.89 | $14.17 | 59m44s | 4h18m |
| LiveCodeBench | N/A | N/A | 77.02s | 3m20s |
| ProgramBench | $24.36 | $70.48 | 1h31m | 5h42m |
| SWE-bench | $1.49 | $0.76 | 16m02s | 10m19s |
| Terminal-Bench 4.0 | $26.33 | $12.02 | 1h45m | 3h09m |
| Vibe Code Bench 1-100 | $71.15 | $9.40 | 4h16m | 1h48m |
| Vibe Code Bench v1.1 | $25.39 | $10.01 | 1h07m | 16m39s |
| CyberBench v1.1 | $1.89 | $2.13 | 16m57s | 30m44s |
| Public Benefits Bench v1.1 | $1.29 | $0.91 | 21m09s | 7m19s |
Results available only for Claude Sonnet 5
- SkillsBench
Results available only for Kimi K3
- Vals RSI Index
- BioMysteryBench
- Time Horizon Index: KSP