gpt-oss API pricing
OpenAI's open-weight models, released under Apache 2.0 in August 2025. Many hosts run them; prices here are the cheapest listed on OpenRouter.
gpt-oss-120b
What it costs in practice
gpt-oss-120b at list prices, no batch discount.
| 1,000 chat replies1,500 tokens in and 300 out each | $0.41 |
|---|---|
| Summarising 100 long reports20,000 tokens in and 800 out each | $0.35 |
| A month of a coding agent400 tasks, 85% of input cached | $117 |
The coding-agent example assumes 85% of input is served from cache, typical for agents that resend the same context each step. Model your own workload
Details
gpt-oss-120bCheapest host listed on OpenRouter. Prices vary by host.
Checked 27 Sep 2026 against OpenRouter listing .
Other gpt-oss models
Because the weights are open, you can also run them yourself. See the local LLM calculator.
| Model | Input / 1M | Output / 1M | Cached input | Context | Released |
|---|---|---|---|---|---|
Open weights · via OpenRouter |
$0.018 | $0.090 | — | 128K | 5 Aug 2025 |
gpt-oss-20b details
gpt-oss-20b
$0.018 / $0.090 per 1M tokens128K context
Cheapest host listed on OpenRouter. Prices vary by host.
Checked 27 Sep 2026 against OpenRouter listing .
Compare gpt-oss-120b
No ready-made comparisons for this family yet.
Price history
All changesNo price changes recorded since we began tracking in June 2026.
OpenAI pricing rules
- Batch and Flex processing cost 50% less.
- For GPT-5.4 and later, prompts longer than 272K tokens are billed at 2× the input price and 1.5× the output price.
- Cached input is billed at about a tenth of the input price.
Questions
How much does gpt-oss-120b cost?
As of 27 Sep 2026, gpt-oss-120b costs $0.15 per million input tokens and $0.60 per million output tokens. Prices checked 27 Sep 2026.
What is the cheapest gpt-oss model?
gpt-oss-20b, at $0.018 / $0.09 per million input / output tokens.
What is gpt-oss-120b's context window?
128K tokens.