Claude Sonnet 5
ECI#20
156Claude Sonnet 5 is a closed-weights model from Anthropic, released June 30, 2026. It has an ECI score of 156 and ranks 20th of 249 tracked models. At the time of its release, it ranked 9th of 225 tracked models.
Claude Sonnet 5 vs select alternatives
| Domain | Benchmark | Claude Sonnet 5 | |||
|---|---|---|---|---|---|
ECI scoreBest score 166 | 156 | 155 | 156 | 156 | |
| Ranking | #20 | #24 | #18 | #19 | |
| Conceptual reasoning | SimpleBenchBest score 82% | ||||
| Games | Chess PuzzlesBest score 72% | ||||
Mystery Game PuzzlesBest score 84% | |||||
| Mathematics | FrontierMath Tiers 1-3 (v2)Best score 94% | ||||
FrontierMath Tier 4 (v2)Best score 98% | |||||
OTIS Mock AIME 2024-2025Best score 100% | |||||
| Science | GPQA DiamondBest score 96% | ||||
| Software engineering | Text Arena (Coding)Best score 1797 | 1539 | 1556 | 1567 | 1518 |
| World knowledge | SimpleQA VerifiedBest score 76% |
