Work
The token estimate
Four characters per token is the usual English average. It is close enough for planning a budget and nowhere near accurate enough for billing, which is why the figure is labelled an estimate.
The Formula
tokens = characters / 4, rounded up, for English text
Four characters per token is the usual English average. It is close enough for planning a budget and nowhere near accurate enough for billing, which is why the figure is labelled an estimate.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| L | Characters | characters | The length of the assembled prompt. |
| n_tok | Rough tokens | tokens | L divided by four and rounded up. |
What Each Symbol Means
Lcharacters
Characters
The length of the assembled prompt.
n_toktokens
Rough tokens
L divided by four and rounded up.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to write chatgpt prompts page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Write ChatGPT Prompts, filed under Everyday Life. Every number the guide produces comes from substituting into this one line.