Model comparison
Claude Sonnet 5.5 vs GPT-6 Astra: Benchmark Comparison
Claude Sonnet 5.5 has the higher score on 13 of 19 shared benchmarks; GPT-6 Astra leads on 6.
The largest observed score gap is 27.14 pts on Terminal-Bench Science , where GPT-6 Astra leads.
Reported ±1 standard-error ranges overlap on 9 of 19 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 | GPT-6 Astra | Gap | Reported uncertainty |
|---|---|---|---|---|
| Vals Index | 69.22% ±0.96 | 66.61% ±1.09 | 2.61 pts | Reported ±1 SE ranges do not overlap |
| Harvey's Legal Agent Benchmark | 2.92% ±1.36 | 5.42% ±1.17 | 2.50 pts | Reported ±1 SE ranges overlap |
| Legal Research Bench | 48.08% ±3.47 | 39.42% ±3.40 | 8.65 pts | Reported ±1 SE ranges do not overlap |
| EMB | 75.71% ±2.44 | 71.70% ±2.48 | 4.01 pts | Reported ±1 SE ranges overlap |
| Finance Agent (v2) | 58.10% ±0.67 | 53.54% ±2.08 | 4.56 pts | Reported ±1 SE ranges do not overlap |
| Tax Agent Bench | 73.39% ±2.98 | 63.34% ±3.15 | 10.06 pts | Reported ±1 SE ranges do not overlap |
| MedCode | 52.92% ±2.12 | 48.49% ±2.13 | 4.43 pts | Reported ±1 SE ranges do not overlap |
| MedScribe | 91.10% ±1.96 | 87.91% ±1.94 | 3.19 pts | Reported ±1 SE ranges overlap |
| ProofBench v1.1 | 100.00% ±0.00 | 99.00% ±1.00 | 1.00 pts | Reported ±1 SE ranges overlap |
| BioMysteryBench | 81.11% ±0.64 | 79.26% ±0.98 | 1.85 pts | Reported ±1 SE ranges do not overlap |
| MysteryMechanism | 49.10% ±3.36 | 53.15% ±3.36 | 4.05 pts | Reported ±1 SE ranges overlap |
| Terminal-Bench Science | 38.57% ±5.86 | 65.71% ±5.71 | 27.14 pts | Reported ±1 SE ranges do not overlap |
| SAGE | 51.77% ±3.41 | 46.37% ±3.44 | 5.41 pts | Reported ±1 SE ranges overlap |
| Code Migration | 69.83% ±4.26 | 67.74% ±4.22 | 2.09 pts | Reported ±1 SE ranges overlap |
| IOI | 83.06% ±3.74 | 100.00% ±0.00 | 16.94 pts | Reported ±1 SE ranges do not overlap |
| Terminal-Bench 4.0 | 53.03% ±1.51 | 57.07% ±3.07 | 4.04 pts | Reported ±1 SE ranges overlap |
| Vibe Code Bench v1.1 | 92.39% ±1.26 | 89.59% ±2.17 | 2.80 pts | Reported ±1 SE ranges overlap |
| CyberBench v1.1 | 59.58% ±5.21 | 41.07% ±2.56 | 18.51 pts | Reported ±1 SE ranges do not overlap |
| SRE Bench | 30.15% ±2.84 | 56.87% ±3.07 | 26.72 pts | Reported ±1 SE ranges do not overlap |
Performance by category
| Category | Claude Sonnet 5.5 average | GPT-6 Astra average |
|---|---|---|
| Index | 69.22% | 66.61% |
| Legal | 25.50% | 22.42% |
| Finance | 69.07% | 62.86% |
| Healthcare | 72.01% | 68.20% |
| Math | 100.00% | 99.00% |
| Science | 56.26% | 66.04% |
| Education | 51.77% | 46.37% |
| Coding | 74.58% | 78.60% |
| Beta | 44.87% | 48.97% |
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 | GPT-6 Astra cost | Claude Sonnet 5.5 latency | GPT-6 Astra latency |
|---|---|---|---|---|
| Vals Index | $20.80 | $19.09 | 1h10m | 25m11s |
| Harvey's Legal Agent Benchmark | $16.61 | $26.16 | 57m44s | 24m49s |
| Legal Research Bench | $14.83 | $10.58 | 1h33m | 24m51s |
| EMB | $8.79 | $5.83 | 36m45s | 13m24s |
| Finance Agent (v2) | $6.55 | $6.82 | 31m43s | 11m33s |
| Tax Agent Bench | $9.25 | $5.80 | 59m21s | 15m01s |
| MedCode | N/A | N/A | 3m59s | 102.86s |
| MedScribe | N/A | N/A | 5m07s | 2m34s |
| ProofBench v1.1 | $0.56 | $1.71 | 5m48s | 5m08s |
| BioMysteryBench | $3.74 | $1.72 | 18m06s | 4m46s |
| MysteryMechanism | $3.45 | $1.56 | 23m30s | 8m09s |
| Terminal-Bench Science | $31.98 | $15.80 | 3h22m | 1h30m |
| SAGE | N/A | N/A | 113.42s | 41.63s |
| Code Migration | $75.83 | $44.36 | 3h20m | 58m30s |
| IOI | $7.52 | $6.50 | 45m51s | 31m40s |
| Terminal-Bench 4.0 | $19.33 | $8.21 | 2h06m | 42m02s |
| Vibe Code Bench v1.1 | $31.25 | $38.51 | 1h01m | 39m04s |
| CyberBench v1.1 | $4.42 | $1.84 | 33m53s | 4m10s |
| SRE Bench | $26.52 | $13.50 | 1h55m | 17m51s |
Results available only for Claude Sonnet 5.5
- Public Benefits Bench v1.1
Results available only for GPT-6 Astra
- Vals RSI Index
- ProgramBench
- Vibe Code Bench 1-100
- CUA-bench
- Time Horizon Index: KSP