Tokens & Pricing
Cost per 1K tokens
The standard way pricing is quoted: dollars per 1,000 tokens, listed separately for input and output. Providers increasingly quote per million tokens, but the per-1K figure is still the mental unit for estimating a call.
Example
A model priced at $0.003 per 1K input tokens and $0.015 per 1K output tokens. A call with 1,500 input and 500 output tokens costs (1.5 × $0.003) + (0.5 × $0.015) = $0.012.
Related terms
Token
The unit AI models read and write, and the unit you're billed in. A token is a chunk of text — often a word, a piece of a word, or a punctuation mark. Models don't see letters or words; they see tokens.
Model tier
The rough class of a model by capability and price. Providers offer a range — small/fast/cheap up to large/slow/expensive — and the price gap between tiers is often 10–30×.
Input tokens (prompt tokens)
The tokens you send into the model — your prompt, the instructions, any documents or history you include. You pay for these whether or not the answer is any good.
Output tokens (completion tokens)
The tokens the model generates back to you. Output tokens almost always cost more per token than input tokens — often 3–5× more — because generating text is the expensive part.