GPT-5 nano
At the Frontier difficulty, GPT-5 nano stays reliable to 4.5K of its 400K advertised window for critical use (1% of the window), at 806K /$ of reliable context.
Frontier difficulty
Hardest tasks, tuned to bend the strongest models
- Critical ≥95%
- 4.5K *
- CI 2.9K to 9.0K
- Right 95% of the time. Use it where a wrong answer is costly.
- Normal ≥85%
- 9.0K *
- CI 2.9K to 17K
- Right 85% of the time. A person reviews the output.
- Exploratory ≥75%
- 13K
- CI 5.2K to 20K
- Right 75% of the time. Fine for drafts and ideation.
Standard difficulty
A moderate task difficulty
- Critical ≥95%
- 262K+ *
- Right 95% of the time. Use it where a wrong answer is costly.
- Normal ≥85%
- 262K+ *
- Right 85% of the time. A person reviews the output.
- Exploratory ≥75%
- 262K+
- Right 75% of the time. Fine for drafts and ideation.
Light difficulty
Lighter tasks, where cheaper and self-hosted models still bend in window
- Critical ≥95%
- 262K+ *
- Right 95% of the time. Use it where a wrong answer is costly.
- Normal ≥85%
- 262K+ *
- Right 85% of the time. A person reviews the output.
- Exploratory ≥75%
- 262K+
- Right 75% of the time. Fine for drafts and ideation.
Usable context is the longest context a model stays at or above a usage bar, read from a fit that borrows strength across the difficulty tiers so the higher bars resolve without deep per-cell sampling. A star marks a bar whose lower confidence bound is not resolved at this depth. Value is reliable context per dollar of input price; self-hosted models are priced by amortized GPU-hours.
| reasoning | reliable (Critical) | % of window | reliable ctx / $ |
|---|---|---|---|
| high reasoning | 4.5K | 1% | 806K /$ |
| medium reasoning | 3.6K | 1% | 1.8M /$ |
| low reasoning | 3.3K | 1% | 4.3M /$ |
Higher reasoning usually buys more usable context but costs more. The leaderboard lists this model once and the Value sort surfaces its most cost-efficient level. Figures are at the Frontier difficulty tier.
Usable context above is the primary measure. As a secondary, difficulty-axis view (how hard a coupled reasoning task it sustains as context grows), GPT-5 nano scores 33.6/100.