gpt-oss-20b

gpt-oss-20b is a budget-tier language model from OpenAI with 20B parameters. gpt-oss-20b is an open-weights model, meaning the weights are publicly available for self-hosting, fine-tuning, and deployment on your own infrastructure — not just through OpenAI's API. The GPT-OSS family is OpenAI's model series for this capability tier.

gpt-oss-20b is priced at $0.04/1M input tokens and $0.15/1M output tokens. Output tokens are 3.8× more expensive than input tokens — this ratio reflects the sequential nature of autoregressive generation, which requires a separate forward pass per output token versus parallel processing of all input tokens simultaneously. At a typical usage pattern of 1,000 input tokens and 500 output tokens per call, gpt-oss-20b costs approximately $0.12 per 1,000 API calls. OpenAI does not publish a prompt caching rate for this model, so repeated long contexts are billed at the standard $0.04/1M input rate.

Its 131K-token context window handles most long-document tasks — roughly 75,000 words or a full novel — without requiring chunking or retrieval augmentation. Median latency (P50 time-to-first-token) is approximately 200ms — fast enough for real-time interactive applications. Throughput is approximately 250 tokens/second — fast enough to stream responses at reading speed with headroom for concurrent requests. Maximum output length is 16K tokens — sufficient for long-form content generation, detailed code files, and extended reports.

gpt-oss-20b is best suited to cost, speed. Supported capabilities include function calling / tool use for agentic workflows, streaming token output for real-time UIs. Function calling support makes it suitable for building AI agents, structured data extraction pipelines, and any workflow requiring the model to invoke external APIs or return typed JSON. When evaluating this model for a specific workload, the most important factors are: context window (does your input fit?), output price (how long are your generations?), and latency (is this interactive or batch?). The pricing table above shows how gpt-oss-20b compares to similar models across these dimensions.

gpt-oss-20b sits in the budget tier — the most cost-efficient models, best for high-volume simple tasks, classification, extraction, and applications where cost per call is the primary constraint. As an open-weights model, gpt-oss-20b can be self-hosted on GPU compute (see the GPU rental comparison on this site) to eliminate per-token API costs entirely — the break-even point versus API pricing depends on your volume and the GPU hourly rate. When comparing gpt-oss-20b to alternatives, use the similar models section on this page to find models at comparable price points with different capability tradeoffs. The intelligence score (62/100) reflects aggregate benchmark performance — a useful proxy for general capability, though real-world performance varies significantly by task type. Always test with your specific prompts and use case before committing to a model for production.