Claude Opus 4.8
ECI#10
158Claude Opus 4.8 is a closed-weights model from Anthropic, released May 28, 2026. It has an ECI score of 158 and ranks 10th of 249 tracked models. At the time of its release, it ranked 4th of 218 tracked models. At $5/Mtok for input tokens and $25/Mtok for output tokens, it is more expensive per token than similarly-capable models.
Input price$5 / 1M tokens
Output price$25 / 1M tokens
ParametersUnknown
Training computeUnknown
Claude Opus 4.8 vs select alternatives
Reasoning
| Domain | Benchmark | Claude Opus 4.8 | |||
|---|---|---|---|---|---|
ECI scoreBest score 166 | 158 | 156 | 162 | 155 | |
| Ranking | #10 | #18 | #5 | #27 | |
| Conceptual reasoning | ARC-AGI-2Best score 95.0% | ||||
| Games | Chess PuzzlesBest score 72.0% | ||||
Earthborne Rangers (EBR-bench)Best score 76.2% | |||||
Mystery Game PuzzlesBest score 84.0% | |||||
| Mathematics | FrontierMath Tiers 1-3 (v2)Best score 93.7% | ||||
FrontierMath Tier 4 (v2)Best score 97.6% | |||||
OTIS Mock AIME 2024-2025Best score 100.0% | |||||
| Science | GPQA DiamondBest score 95.8% | ||||
| World knowledge | SimpleQA VerifiedBest score 75.6% |
