GPT-5 Pro 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-5 Pro and gpt-oss-20b.
GPT-5 Pro
GPT-5 Pro is OpenAI’s most advanced model, offering major improvements in reasoning, code quality, and user experience. It is optimized for complex tasks that require step-by-step reasoning, instruction following, and...
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-5 Pro | gpt-oss-20b |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Context Window | 400,000 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 | 2025-10-06 | 2025-08-05 |
API Pricing Comparison
Input Price per Million Tokens
GPT-5 Pro
$15.00
gpt-oss-20b
$0.03
Output Price per Million Tokens
GPT-5 Pro
$120.00
gpt-oss-20b
$0.14
Want to test both models live?
Run side-by-side prompt prompts in our dynamic Sandbox. Check execution speeds, latency metrics, and compute actual costs in real-time.
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-5 Pro Quirks & Gotchas
No developer gotchas reported.
gpt-oss-20b Quirks & Gotchas
No developer gotchas reported.