OpenAI API pricing per million tokens

How much does the OpenAI API cost per million tokens?

OpenAI charges per million tokens, with separate rates for input, cached input and output, and each model has its own rates. The OpenAI pricing page splits rates into short context (272K input tokens or fewer) and long context (more than 272K input tokens).

Model	Input	Cached input	Output
gpt-6-astra	$10.00	$1.00	$50.00
gpt-6.1-sol	$2.00	$0.10	$10.00
gpt-6.1-terra	$1.00	$0.05	$5.00
gpt-6-sol	$2.00	$0.20	$10.00
gpt-6-luna	$0.10	$0.01	$0.50
gpt-5.6-sol	$4.00	$0.40	$20.00
gpt-5.6-terra	$2.00	$0.20	$12.00
gpt-5.6-luna	$0.20	$0.02	$1.20

The page says GPT-5.6 Sol’s promotional pricing is available at least through November 21, 2026. Older models, such as gpt-5.5, gpt-5.4 and gpt-4.1, are listed on the same page.

What does long context cost?

Requests over 272K input tokens cost more per token. These are the long context rates on the same page.

Model	Input	Cached input	Output
gpt-6-astra	$20.00	$2.00	$75.00
gpt-6.1-sol	$4.00	$0.20	$15.00
gpt-6.1-terra	$2.00	$0.10	$7.50
gpt-6-sol	$4.00	$0.40	$15.00
gpt-6-luna	$0.20	$0.02	$0.75
gpt-5.6-sol	$8.00	$0.80	$30.00
gpt-5.6-terra	$4.00	$0.40	$18.00
gpt-5.6-luna	$0.40	$0.04	$1.80

How does prompt caching change the price?

Reused prompt prefixes are billed at the cached input rate, which OpenAI’s prompt caching guide says is “discounted up to 95%.” Caching is on by default for supported models.

On GPT-5.6 and later, writing a prefix to the cache has its own rate. Per the same guide, the default 30-minute write costs 1.25x the uncached input rate. A 12-hour write, set in the Responses API, costs 2.5x. OpenAI notes these are total write rates, not surcharges on top of ordinary input. A prefix must be at least 1,024 tokens to be cached on these models.

Model	30-minute write	12-hour write
gpt-6-astra	$12.50	$25.00
gpt-6.1-sol	$2.50	$5.00
gpt-6.1-terra	$1.25	$2.50
gpt-6-sol	$2.50	$5.00
gpt-6-luna	$0.125	$0.25
gpt-5.6-sol	$5.00	$10.00
gpt-5.6-terra	$2.50	$5.00
gpt-5.6-luna	$0.25	$0.50

How much does the Batch API save?

The Batch API costs half of standard rates, which OpenAI describes as a “50% cost discount compared to synchronous APIs.” Each batch completes within 24 hours, and batch jobs use a separate pool of rate limits.

Model	Input	Cached input	Output
gpt-6-astra	$5.00	$0.50	$25.00
gpt-6.1-sol	$1.00	$0.05	$5.00
gpt-6.1-terra	$0.50	$0.025	$2.50
gpt-6-sol	$1.00	$0.10	$5.00
gpt-6-luna	$0.05	$0.005	$0.25
gpt-5.6-sol	$2.00	$0.20	$10.00
gpt-5.6-terra	$1.00	$0.10	$6.00
gpt-5.6-luna	$0.10	$0.01	$0.60

What does Flex processing cost?

Flex processing costs the same as Batch for the models above, in exchange for slower responses and occasional resource unavailability. OpenAI’s flex processing guide says “Tokens are priced at Batch API rates, with additional discounts from prompt caching.” The Flex table on the pricing page matches the Batch table above for these eight models.

Flex is in beta with limited model availability. When Flex lacks capacity it returns a 429 Resource Unavailable error, and OpenAI says you are not charged for it.

What does Fast mode cost?

Fast mode costs twice the standard rate for every model in the table below. The pricing page notes that Priority processing was renamed Fast mode on July 30, 2026.

Model	Input	Cached input	Output
gpt-6-astra	$20.00	$2.00	$100.00
gpt-6.1-sol	$4.00	$0.20	$20.00
gpt-6.1-terra	$2.00	$0.10	$10.00
gpt-6-sol	$4.00	$0.40	$20.00
gpt-6-luna	$0.20	$0.02	$1.00
gpt-5.6-sol	$8.00	$0.80	$40.00
gpt-5.6-terra	$4.00	$0.40	$24.00
gpt-5.6-luna	$0.40	$0.04	$2.40

The page also lists an Ultrafast tier for two models. gpt-6-astra is $60.00 input, $6.00 cached input and $300.00 output per 1M tokens. gpt-6.1-sol is $12.00 input, $0.60 cached input and $60.00 output.

Are there other surcharges?

Yes, for some endpoints. Per the pricing page, regional processing (data residency) endpoints are charged a 10% uplift for models released on or after March 5, 2026. FedRAMP endpoints are also charged a 10% uplift.

How do you pay for OpenAI API usage?

Most accounts pay in advance. OpenAI’s prepaid billing article says new API accounts use prepaid billing, and purchased credits expire after 1 year. The full picture, with invoices, tiers and spend limits, is in how OpenAI and Anthropic API billing works.

To turn these rates into a monthly figure, try the AI API cost calculator. For ways to lower the bill, read how to cut LLM API costs or how to cut OpenAI API costs on the ernd blog.