GPT-5.5
ECI#10
159GPT-5.5 is a closed-weights model from OpenAI, released April 23, 2026. It has an ECI score of 159 and ranks 10th of 253 tracked models. At the time of its release, it ranked 2nd of 209 tracked models.
GPT-5.5 vs select alternatives
| Domain | Benchmark | GPT-5.5 | |||
|---|---|---|---|---|---|
ECI scoreBest score 167 | 159 | 159 | 156 | 155 | |
| Ranking | #10 | #11 | #22 | #31 | |
| Games | Chess PuzzlesBest score 72% | ||||
Earthborne Rangers (EBR-bench)Best score 76% | |||||
Mystery Game PuzzlesBest score 84% | |||||
| Mathematics | FrontierMath Tiers 1-3 (v2)Best score 94% | ||||
FrontierMath Tier 4 (v2)Best score 100% | |||||
| Multimodal | Furniture Assembly BenchmarkBest score 83% | ||||
| Software engineering | MirrorCodeBest score 77% | ||||
SWE-bench VerifiedBest score 83% | |||||
| World knowledge | SimpleQA VerifiedBest score 76% |
