The Price of a Call

Token problems: 6 of 20

Token problems: the workbook

1. Count the Tokens

2. Subword Splitting

3. Punctuation Counts

4. Tokens per Word

5. Will It Fit?

6. The Price of a Call

7. Two Kinds of Token

8. Input or Output?

9. The Two-Part Bill

10. End-to-End Call Cost

11. Comparing Three Calls

12. The Average Call

13. The System Prompt

14. The System Prompt Tax

15. Calls in a Budget

16. Tokens on a Budget

17. How Long Will It Take?

18. The Split Matters

19. Pricing per Million Tokens

20. Tokens from the Bill

What does a model API call cost? Every call is billed by the token: count the 100-token blocks in the call, then multiply by the price per block. Real APIs quote per million tokens, but these problems use cents per 100 to keep the arithmetic easy to follow by hand. An agent that calls the model on every user turn pays this cost each time.

Problem

An AI agent processes a call of 600 tokens. The model is priced at 2 cents per 100 tokens. What does this call cost?

Count the 100-token blocks

Multiply by the price per block

Practice 1

An AI agent processes a call of 2,000 tokens. The model is priced at 3 cents per 100 tokens. What does this call cost?

Count the 100-token blocks

Multiply by the price per block

Practice 2

An AI agent processes a call of 800 tokens. The model is priced at 5 cents per 100 tokens. What does this call cost?

Count the 100-token blocks

Multiply by the price per block

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Next:
7. Two Kinds of Token