Claude Sonnet 5.5 vs Gemini 3.8 Flash: Benchmark Comparison
Claude Sonnet 5.5 has the higher score on 19 of 21 shared benchmarks; Gemini 3.8 Flash leads on 2.
The largest observed score gap is 52.00 pts on ProofBench v1.1 , where Claude Sonnet 5.5 leads.
Reported ±1 standard-error ranges overlap on 2 of 21 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 5.5 | Gemini 3.8 Flash | Gap | Reported uncertainty |
|---|---|---|---|---|
| Vals Index | 67.04% ±0.92 | 54.83% ±1.03 | 12.21 pts | Reported ±1 SE ranges do not overlap |
| Harvey's Legal Agent Benchmark | 2.92% ±1.36 | 10.00% ±2.42 | 7.08 pts | Reported ±1 SE ranges do not overlap |
| Legal Research Bench | 48.08% ±3.47 | 38.94% ±3.39 | 9.13 pts | Reported ±1 SE ranges do not overlap |
| EMB | 75.71% ±2.44 | 72.20% ±2.42 | 3.52 pts | Reported ±1 SE ranges overlap |
| Finance Agent (v2) | 58.10% ±0.67 | 61.44% ±0.13 | 3.33 pts | Reported ±1 SE ranges do not overlap |
| Tax Agent Bench | 41.96% ±3.56 | 32.12% ±3.37 | 9.84 pts | Reported ±1 SE ranges do not overlap |
| MedCode | 52.92% ±2.12 | 48.13% ±2.18 | 4.79 pts | Reported ±1 SE ranges do not overlap |
| MedScribe | 91.10% ±1.96 | 84.50% ±1.94 | 6.61 pts | Reported ±1 SE ranges do not overlap |
| ProofBench v1.1 | 100.00% ±0.00 | 48.00% ±5.02 | 52.00 pts | Reported ±1 SE ranges do not overlap |
| BioMysteryBench | 81.11% ±0.64 | 62.22% ±1.70 | 18.89 pts | Reported ±1 SE ranges do not overlap |
| MysteryMechanism | 49.10% ±3.36 | 36.49% ±3.24 | 12.61 pts | Reported ±1 SE ranges do not overlap |
| Terminal-Bench Science | 45.71% ±6.00 | 8.57% ±3.37 | 37.14 pts | Reported ±1 SE ranges do not overlap |
| SAGE | 51.77% ±3.41 | 35.06% ±3.36 | 16.71 pts | Reported ±1 SE ranges do not overlap |
| Code Migration | 69.83% ±4.26 | 36.55% ±4.18 | 33.28 pts | Reported ±1 SE ranges do not overlap |
| IOI | 83.06% ±3.74 | 56.94% ±2.26 | 26.11 pts | Reported ±1 SE ranges do not overlap |
| ProgramBench | 6.50% ±1.75 | 1.00% ±0.70 | 5.50 pts | Reported ±1 SE ranges do not overlap |
| Terminal-Bench 4.0 | 64.14% ±1.01 | 19.19% ±2.52 | 44.95 pts | Reported ±1 SE ranges do not overlap |
| Vibe Code Bench v1.1 | 92.39% ±1.26 | 78.65% ±3.88 | 13.74 pts | Reported ±1 SE ranges do not overlap |
| CyberBench v1.1 | 59.58% ±5.21 | 43.75% ±2.21 | 15.83 pts | Reported ±1 SE ranges do not overlap |
| SRE Bench | 30.15% ±2.84 | 11.07% ±1.94 | 19.08 pts | Reported ±1 SE ranges do not overlap |
| Public Benefits Bench v1.1 | 67.19% ±1.22 | 65.29% ±1.24 | 1.89 pts | Reported ±1 SE ranges overlap |
Performance by category
| Category | Claude Sonnet 5.5 average | Gemini 3.8 Flash average |
|---|---|---|
| Legal | 25.50% | 24.47% |
| Finance | 58.59% | 55.25% |
| Healthcare | 72.01% | 66.32% |
| Math | 100.00% | 48.00% |
| Science | 58.64% | 35.76% |
| Education | 51.77% | 35.06% |
| Coding | 63.18% | 38.47% |
| Cyber | 44.87% | 27.41% |
| Social Mobility | 67.19% | 65.29% |
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 5.5 cost | Gemini 3.8 Flash cost | Claude Sonnet 5.5 latency | Gemini 3.8 Flash latency |
|---|---|---|---|---|
| Vals Index | $21.34 | $5.73 | 1h18m | 51m57s |
| Harvey's Legal Agent Benchmark | $16.61 | $3.66 | 57m44s | 29m21s |
| Legal Research Bench | $14.83 | $1.63 | 1h33m | 5m24s |
| EMB | $8.79 | $8.24 | 36m45s | 12m49s |
| Finance Agent (v2) | $6.55 | $2.00 | 31m43s | 3m21s |
| Tax Agent Bench | $9.25 | $0.86 | 59m21s | 2m58s |
| MedCode | N/A | N/A | 3m59s | 42.89s |
| MedScribe | N/A | N/A | 5m07s | 21.14s |
| ProofBench v1.1 | $0.56 | $0.60 | 5m48s | 6m09s |
| BioMysteryBench | $3.74 | $1.55 | 18m06s | 5m27s |
| MysteryMechanism | $3.45 | $1.73 | 23m30s | 5m22s |
| Terminal-Bench Science | $30.43 | $5.64 | 2h39m | 55m11s |
| SAGE | N/A | N/A | 113.42s | 28.64s |
| Code Migration | $75.83 | $18.49 | 3h20m | 2h37m |
| IOI | $7.52 | $3.98 | 45m51s | 14m20s |
| ProgramBench | $35.86 | $10.93 | 2h07m | 46m39s |
| Terminal-Bench 4.0 | $16.51 | $8.77 | 1h22m | 1h48m |
| Vibe Code Bench v1.1 | $31.25 | $6.87 | 1h01m | 8m39s |
| CyberBench v1.1 | $4.42 | $1.31 | 33m53s | 9m49s |
| SRE Bench | $26.52 | $27.46 | 1h55m | 2h28m |
| Public Benefits Bench v1.1 | $4.25 | $1.01 | 1h15m | 3m21s |
Results available only for Claude Sonnet 5.5
None.
Results available only for Gemini 3.8 Flash
- Vals RSI Index
- LegalBench
- MortgageTax
- TaxEval v2
- GPQA Diamond
- MMLU Pro
- MMMU Pro
- LiveCodeBench
- SkillsBench
- SWE-bench
- Vibe Code Bench 1-100
- CUA-bench
- Time Horizon Index: KSP