gpt-oss-120b vs gpt-oss-20b
How do these models stack up? Below is an expert side-by-side comparison of specifications, context window capacity, live pricing per million tokens, and standardized benchmark scores for gpt-oss-120b and gpt-oss-20b.
gpt-oss-120b
gpt-oss-120b is an open-weight, 117B-parameter Mixture-of-Experts (MoE) language model from OpenAI designed for high-reasoning, agentic, and general-purpose production use cases. It activates 5.1B parameters per forward pass and is optimized...
gpt-oss-20b
gpt-oss-20b is an open-weight 21B parameter model released by OpenAI under the Apache 2.0 license. It uses a Mixture-of-Experts (MoE) architecture with 3.6B active parameters per forward pass, optimized for...
Technical Specifications
| Specification | gpt-oss-120b | gpt-oss-20b |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Context Window | 131,072 tokens | 131,072 tokens |
| Agent Suitability | N/A | N/A |
| Time to First Token (TTFT) | N/A | N/A |
| Deployment Model | managed api | managed api |
| Production Stability | stable | stable |
| API Available | Yes | Yes |
| Released Date | 2025-08-05 | 2025-08-05 |
API Pricing Comparison
Input Price per Million Tokens
gpt-oss-120b
$0.03
gpt-oss-20b
$0.03
Output Price per Million Tokens
gpt-oss-120b
$0.15
gpt-oss-20b
$0.14
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Benchmark Performance Metrics
Scores show the raw performance percentages verified across key evaluation suites. Higher bars indicate superior accuracy and capability in that domain.
gpt-oss-120b Quirks & Gotchas
No developer gotchas reported.
gpt-oss-20b Quirks & Gotchas
No developer gotchas reported.