Model Tracker

gpt-oss-20b

gpt-oss-20b is an AI model made by OpenAI. OpenAI released it on 5 August 2025. It is generally available. It takes text and returns text.

OpenAI

gpt-oss-20b is an AI model made by OpenAI. OpenAI released it on 5 August 2025. It is generally available. It takes text and returns text. Its context window is 131,072 tokens. Its longest answer is 131,072 tokens. Its weights are open. Its licence is Apache 2.0. Its knowledge cutoff is 1 June 2024.

Released: 5 August 2025 — openai.com, read 16 October 2026
Status: Generally available — developers.openai.com, read 16 October 2026
Takes: Text — developers.openai.com, read 16 October 2026
Returns: Text — developers.openai.com, read 16 October 2026
Open weights: Yes — openai.com, read 16 October 2026
Licence: Apache 2.0 — openai.com, read 16 October 2026
Context window: 131,072 tokens — developers.openai.com, read 16 October 2026
Longest answer: 131,072 tokens — developers.openai.com, read 16 October 2026
Knowledge cutoff: 1 June 2024 — developers.openai.com, read 16 October 2026
API price, input: Not confirmed: OpenAI says the model is not served through its API, and its API pricing page provides no standard input price for this model.
API price, output: Not confirmed: OpenAI says the model is not served through its API, and its API pricing page provides no standard output price for this model.
Where: Downloadable weights — help.openai.com, read 16 October 2026
Parameters: 21,000,000,000 — developers.openai.com, read 16 October 2026
Model card: Not confirmed: two readings disagree: https://cdn.openai.com/pdf/419b6906-9da6-406c-a19d-1bb078ac7637/oai_gpt-oss_model_card.pdf and https://openai.com/index/gpt-oss-model-card/

Benchmarks

Measured by others, not by the maker: each score with the name the measurer gives the model and the setting it ran, its day and its licence.

Arena

Text Arena, gpt-oss-20b: 1,317 (1,311–1,324, 10,419 votes), published 15 October 2026

Arena’s leaderboard dataset (lmarena-ai/leaderboard-dataset on Hugging Face), CC BY 4.0: ratings from people’s votes between two anonymous models, as Arena publishes them. Data · CC BY 4.0

Epoch AI

Epoch Capabilities Index, gpt-oss-20b: 137.8 (133.2–139.8), as of 19 October 2026
GPQA Diamond, gpt-oss-20b_medium: 60.8% (± 2.5), run 27 August 2026
GPQA Diamond, gpt-oss-20b_low: 53.2% (± 2.5), run 27 August 2026
GPQA Diamond, gpt-oss-20b_high: 46.0% (± 3.6), run 6 August 2026
OTIS Mock AIME 2024–2025, gpt-oss-20b_medium: 65.3% (± 5.9), run 27 August 2026
OTIS Mock AIME 2024–2025, gpt-oss-20b_high: 50.8% (± 6.7), run 27 August 2026
OTIS Mock AIME 2024–2025, gpt-oss-20b_low: 40.3% (± 6.3), run 27 August 2026

Epoch AI, ‘Capabilities & benchmarking’, epoch.ai/benchmarks, CC BY 4.0: Epoch AI’s own runs and its Capabilities Index. Data · CC BY 4.0

Questions

When was gpt-oss-20b released?

OpenAI released gpt-oss-20b on 5 August 2025.

Is gpt-oss-20b still available?

Yes: it is generally available, as OpenAI states it.

What is the context window of gpt-oss-20b?

The context window of gpt-oss-20b is 131,072 tokens, as OpenAI prints it.

Are the weights of gpt-oss-20b open?

Yes: OpenAI publishes the weights of gpt-oss-20b for download.

What is the licence of gpt-oss-20b?

The licence of gpt-oss-20b is Apache 2.0, as OpenAI names it.

What does gpt-oss-20b take and return?

gpt-oss-20b takes text and returns text.

What is the knowledge cutoff of gpt-oss-20b?

The knowledge cutoff of gpt-oss-20b is 1 June 2024.

How many parameters does gpt-oss-20b have?

gpt-oss-20b has 21,000,000,000 parameters, as OpenAI publishes it.

Sources

Introducing gpt-oss (read 16 October 2026)
gpt-oss-20b Model | OpenAI API (read 16 October 2026)
OpenAI open-weight models (gpt-oss) (read 16 October 2026)
Pricing | OpenAI API (read 16 October 2026)
gpt-oss-120b & gpt-oss-20b Model Card (read 16 October 2026)

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