OpenAI · Released Aug 5, 2025GPT OSS 20B
Open GPT reasoning model for self-hosted agents and controllable deployments.
- Capability
- 137.8ECI · #108 of 148
- Input
- $0.07per 1M tokens
- Output
- $0.295per 1M tokens
- Context
- 131K33K max output
What it costs
- Input
- $0.07per million tokens
- Output
- $0.295per million tokens
- Blended (3:1)
- $0.126cheaper than 88% of priced models
Typical monthly bills
| Monthly usage | Estimated cost |
|---|---|
| Side project2M input + 0.5M output tokens | $0.287 |
| Team assistant25M input + 5M output tokens | $3.23 |
| Production app250M input + 50M output tokens | $32.25 |
Median of 18 paid API providers on models.dev.
Independent benchmarks
#108 of 148 scored models
The shaded band is Epoch AI’s confidence range (133.0–139.6); the tick marks the median scored model.
Scores from Epoch AI, run independently of OpenAI.
The details
- Lab
- OpenAI
- Released
- Aug 5, 2025
- Context window
- 131,072 tokens
- Max output
- 32,768 tokens
- Inputs
- Text
- Output
- Text
- Reasoning
- Always on
- Tool calling
- Yes
- Structured output
- Yes
- Weights
- Open weights
- Availability
- 19 API providerslisted on models.dev
More from OpenAI
About GPT OSS 20B
How much does GPT OSS 20B cost?
GPT OSS 20B costs $0.07 input / $0.295 output per million tokens (median across 18 API providers). At a 3:1 input-to-output mix that is $0.126 per million tokens, cheaper than 88% of the 360 priced models we track.
What is the context window of GPT OSS 20B?
GPT OSS 20B accepts up to 131,072 tokens per request and can write up to 32,768 tokens in one response.
How good is GPT OSS 20B?
Epoch AI gives GPT OSS 20B a Capabilities Index score of 137.8 (likely range 133.0–139.6), ranking it #108 of 148 models Epoch has scored. Epoch AI benchmark results: GPQA Diamond 60.8%, OTIS Mock AIME 2024–2025 65.3%.
Is GPT OSS 20B open source?
Yes. OpenAI publishes the weights, so it can be downloaded and self-hosted.
What inputs does GPT OSS 20B support?
GPT OSS 20B accepts text and replies in text. It is a reasoning model, supports tool calling and can return structured JSON output.
When was GPT OSS 20B released?
OpenAI released GPT OSS 20B on Aug 5, 2025.
What are the best alternatives to GPT OSS 20B?
The closest current models from other labs on capability, price and release date are Qwen3.5 9B (Alibaba (Qwen), ECI 139.5, $0.10 / $0.15), Gemini 2.5 Flash-Lite (Google, ECI 133.9, $0.10 / $0.40), Mistral Small 3.2 (Mistral AI, ECI 131.7, $0.10 / $0.30) and DeepSeek-R1-Distill-Qwen-32B (DeepSeek, ECI 137.4).