GPT-5 nano vs GPT OSS 20B: Specs & Benchmark Comparison
| Characteristic | GPT-5 nano | GPT OSS 20B |
|---|---|---|
| Company | OpenAI | OpenAI |
| Release Date | August 7, 2025 | August 5, 2025 |
| Parameters | — | 20B |
| Multimodal | Yes | Yes |
| Context (input) | 400K | 131K |
| Context (output) | 128K | 30K |
| Input Price / 1M | $0.05 | $0.10 |
| Output Price / 1M | $0.40 | $0.50 |
| Average Score | 0.5 | 0.4 |
| Benchmarks | ||
| Humanity's Last Exam | 0.1 | 0.1 |
| GPQA | 0.7 | 0.7 |
Visual Benchmark Comparison
GPT-5 nano
GPT OSS 20B
Humanity's Last Exam0.1 vs 0.1
0.1
0.1
GPQA0.7 vs 0.7
0.7
0.7
Verdict
GPT-5 nano leads in 2 out of 4 comparison categories.
Overall Performance
Both models show comparable average scores: GPT-5 nano — 0.5, GPT OSS 20B — 0.4.
API Cost
GPT-5 nano is 1.3x cheaper: input $0.05/1M vs $0.10/1M tokens.
Context Window
GPT-5 nano supports a larger context: 400K vs 131K tokens.
Recency
Both models were released around the same time: 8/7/2025 and 8/5/2025.
More About These Models
The GPT-5 nano and GPT OSS 20B comparison is updated for 2026. Data includes benchmark results, API pricing, context window size and other specifications. For more detailed information, visit the GPT-5 nano or GPT OSS 20B page. See also the complete list of AI model comparisons.