GPT-5 nano
ECI#114
139GPT-5 nano is a closed-weights model from OpenAI, released August 7, 2025. It has an ECI score of 139 and ranks 114th of 249 tracked models. At the time of its release, it ranked 25th of 159 tracked models. At $0.05/Mtok for input tokens and $0.40/Mtok for output tokens, it is less expensive per token than similarly-capable models.
Input price$0.05 / 1M tokens
Output price$0.40 / 1M tokens
ParametersUnknown
Training computeUnknown
GPT-5 nano vs select alternatives
Reasoning
| Domain | Benchmark | GPT-5 nano | |||
|---|---|---|---|---|---|
ECI scoreBest score 166 | 139 | 138 | 140 | 140 | |
| Ranking | #114 | #121 | #109 | #106 | |
| Conceptual reasoning | ARC-AGI-2Best score 95.0% | ||||
ARC-AGI-1Best score 98.5% | |||||
| Games | Chess PuzzlesBest score 72.0% | ||||
Mystery Game PuzzlesBest score 84.0% | |||||
| Mathematics | MATH Level 5Best score 98.1% | ||||
OTIS Mock AIME 2024-2025Best score 100.0% | |||||
| Science | GPQA DiamondBest score 95.8% | ||||
| Software engineering | Terminal-Bench 2.0Best score 84.7% | ||||
WeirdML (v2)Best score 92.9% |
