gpt-oss-20b
ECI#121
138gpt-oss-20b is an open-weights model from OpenAI, released August 5, 2025. It has an ECI score of 138 and ranks 121st of 249 tracked models. At the time of its release, it ranked 29th of 156 tracked models. At $0.04/Mtok for input tokens and $0.15/Mtok for output tokens, it is less expensive per token than similarly-capable models.
Input price$0.04 / 1M tokens
Output price$0.15 / 1M tokens
Parameters2.1e10
Training compute5.5e23 FLOP
gpt-oss-20b vs select alternatives
Reasoning
| Domain | Benchmark | gpt-oss-20b | |||
|---|---|---|---|---|---|
ECI scoreBest score 166 | 138 | 137 | 140 | 137 | |
| Ranking | #121 | #125 | #107 | #124 | |
| Conceptual reasoning | LMCABest score 63.3 | 14.5 | 25.6 | 19.0 | 22.4 |
DTBenchBest score 98.4% | |||||
| Games | Chess PuzzlesBest score 72.0% | ||||
| Mathematics | OTIS Mock AIME 2024-2025Best score 100.0% | ||||
| Science | CritPtBest score 32.3% | ||||
SciCodeBest score 62.0% | |||||
GPQA DiamondBest score 95.8% | |||||
| Software engineering | ALE-BenchBest score 2176.9 | 566.0 | 558.1 | — | — |
WeirdML (v2)Best score 92.9% |
