OpenAI: gpt-oss-120b API Pricing
OpenAI: gpt-oss-120b costs $0.150 per 1M input tokens and $0.600 per 1M output tokens (cache reads: $0.075). Context window: 131K. Prices verified 2026-10-21 · source
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Token economics
| Token type | Price | vs base input |
|---|---|---|
| Standard input | $0.150 | — |
| Cache read | $0.075 | −50% |
| Output | $0.600 | — |
Prompt caching stores repeated context server-side: reads cost far less, but writes carry a one-time premium.
Higher effort = deeper thinking = more reasoning tokens billed as output.
Training data ends here — newer events require retrieval or web search.
What would OpenAI: gpt-oss-120b cost you per month?
| Workload | Requests/mo | Avg tokens (in/out) | Est. monthly cost |
|---|---|---|---|
| Light chatbot | 10,000 | 800 / 400 | $3.60 |
| Coding agent | 5,000 | 8,000 / 2,000 | $12.00 |
| RAG pipeline | 30,000 | 4,000 / 500 | $27.00 |
| Doc summarizer | 2,000 | 20,000 / 1,000 | $7.20 |
Estimates use list prices without prompt caching. Caching can cut input cost by up to 90% on repeated context.
About OpenAI: gpt-oss-120b
gpt-oss-120b is an open-weight, 117B-parameter Mixture-of-Experts (MoE) language model from OpenAI designed for high-reasoning, agentic, and general-purpose production use cases. It activates 5.1B parameters per forward pass and is optimized...
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Frequently asked questions
How much does OpenAI: gpt-oss-120b cost?
OpenAI: gpt-oss-120b costs $0.150 per 1M input tokens and $0.600 per 1M output tokens; cached input tokens cost $0.075 per 1M. Verified 2026-10-21 — provider source.
What is the context window?
131K tokens, with up to 66K output tokens per response. That's roughly 164 pages of text in a single request.
Does it support prompt caching?
Yes — cached input is $0.075/1M, about 50% cheaper than standard input. Agents and RAG workloads with repeated context benefit most.
What's a cheaper alternative?
ScaleDown: Summarize saves about 90% on a typical workload with comparable quality.
Official resources
- OpenAI: gpt-oss-120b on OpenRouter — live endpoint, pricing source of record.
- Artificial Analysis benchmarks → — independent intelligence and performance analysis.
- OpenAI pricing → — first-party pricing and billing details.
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