AI by Hand ✍️

AI by Hand ✍️

The Billing Line

Labelling where input ends

Prof. Tom Yeh's avatar
Prof. Tom Yeh
May 28, 2026
∙ Paid

Library › Token Problems

  1. Tokenization

  2. Subword Tokens

  3. Non-Word Tokens

  4. Token Ratio

  5. Headroom

  6. Token Pricing

  7. Prompt and Completion

  8. The Billing Line

  9. Asymmetric Pricing

  10. Words to Cents

  11. Token Mix

  12. Usage Forecast

  13. Standing Instructions

  14. Fixed Overhead

  15. Budget Ceiling

  16. Token Allowance

  17. Two Speeds

  18. Output Bound

  19. Rate Cards

  20. Usage Audit

Are all the tokens in a call billed the same way? No. Every token is either input (what you send) or output (what the model generates), each billed at its own rate. The boundary between them is the dividing line between two different prices. Labeling each token is the first step to seeing where an agent's cost comes from.

Paid members: the worksheet and its printable PDF are below ↓

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