What it is and what it is for
This calculator estimates what you will pay to use a language model through an API. Providers charge per token, a chunk of text roughly four characters long, and nearly always separate the tokens you send (input) from the tokens the model writes (output). Output is usually several times more expensive than input, so looking at one number alone gives a misleading picture of the real bill.
Use it to compare providers, to budget a project before writing any code, or to spot which part of an application burns the most money. Prices are typed in by hand because they change often, which means the tool never goes out of date.
How to use it, step by step
- Type how many input tokens you expect to send in total, adding instructions, context and user messages.
- Type how many output tokens you expect back. When unsure, use between half and double the input depending on the task.
- Copy the price per million input tokens and per million output tokens from your provider's pricing page.
- Press Calculate. The result appears in US dollars with up to four decimals.
- Repeat with other prices to compare models and keep the one that balances quality and cost best.
Worked example
Picture an assistant that handles 1,000,000 input tokens and generates 500,000 output tokens per month. With a model charging 3 dollars per million input and 15 per million output, the cost is 3 plus 7.50, which is 10.50 dollars. Switch to a cheaper model at 0.5 and 2 dollars and the same usage drops to 1.50 dollars. The gap looks small in one month but multiplies quickly with thousands of users.
Frequently asked questions
What is a token?
It is the smallest unit of text a model processes. In English one word is usually between one and two tokens, and one hundred tokens are about seventy-five words.
Why does output cost more than input?
Generating text takes more computation than reading it, because the model produces each token one after another. Providers therefore set a higher price for output.
Does the result include taxes or discounts?
No. It is an estimate based on list prices. Volume discounts, prompt caching and local taxes can change the final invoice.
Can I use commas or decimal points?
Yes. In the English version type 1.5 or 1,500.25 and the tool reads the format for you.