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

OpenAI: gpt-oss-20b supports a context window of 131K tokens.

Is OpenAI: gpt-oss-20b free to use?

OpenAI: gpt-oss-20b is a paid model. It costs $0.018 per million input tokens and $0.090 per million output tokens.

How is LLM API pricing calculated?

LLM pricing has two components: input tokens (everything you send) and output tokens (what the model generates). Total cost = (prompt tokens × input rate + output tokens × output rate) / 1,000,000 × number of requests.

OpenAI: gpt-oss-20b API Pricing — $0.018 Input / $0.090 Output per 1M Tokens

Q: How much does OpenAI: gpt-oss-20b cost?

OpenAI: gpt-oss-20b costs $0.018 per million input tokens and $0.090 per million output tokens via OpenRouter. Pricing was last updated Oct 29, 2026.

OpenAI: gpt-oss-20b by OpenAI — $0.018 input / $0.090 output per 1M tokens via OpenRouter. Context: 131K tokens. Pricing last updated Oct 29, 2026.

Input / 1M tokens

$0.018

Output / 1M tokens

$0.090

Provider

OpenAI

Context window

131K tokens

Via

OpenRouter

Cost at common usage volumes

Usage	Daily	Monthly
Chatbot (100/day)	$0.012	$0.36
Small app (1K/day)	$0.063	$1.89
Mid-scale (10K/day)	$0.810	$24.30
Large scale (100K/day)	$18.00	$540.00

Model ID: openai/gpt-oss-20b
Data source: OpenRouter public API — updated Oct 29, 2026.

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About OpenAI: gpt-oss-20b

OpenAI: gpt-oss-20b is an LLM developed by OpenAI. Input costs $0.018 per million tokens and output costs $0.090 per million tokens via OpenRouter. It supports a context window of 131K tokens.

Pricing Details

Via the OpenRouter API:

Input tokens: $0.018 per 1 million tokens
Output tokens: $0.090 per 1 million tokens

A token is roughly 0.75 words. For context: a typical user message of 100 words is approximately 133 tokens; a 500-word system prompt is about 650 tokens.

How Much Does OpenAI: gpt-oss-20b Cost?

For a typical chatbot application (1,000 requests/day, 1,000 prompt tokens and 500 output tokens per request):

Daily cost: $0.0630
Monthly cost: $1.890

Accessing OpenAI: gpt-oss-20b via OpenRouter

OpenRouter provides a unified API for 200+ LLMs including OpenAI: gpt-oss-20b. You can use it with any OpenAI-compatible SDK by setting the base URL to https://openrouter.ai/api/v1 and using your OpenRouter API key. The model ID is openai/gpt-oss-20b.

Compare OpenAI: gpt-oss-20b with Other Models

Use the AI Model Cost Comparison tool to compare OpenAI: gpt-oss-20b against GPT-4o, Claude 3.5 Sonnet, Gemini 1.5 Pro, or any other model side by side. Or use the LLM API Cost Calculator to browse all 456+ models sorted by cost for your specific usage.

Frequently Asked Questions

Yes. OpenAI: gpt-oss-20b is available on OpenRouter with the model ID openai/gpt-oss-20b. OpenRouter provides a unified API compatible with OpenAI's SDK format.