Percentages
Recovering the whole from the part
Type three. Divide rather than multiply — this is the step people most often invert.
The Formula
Whole = Part / (Percentage / 100)
Type three. Divide rather than multiply — this is the step people most often invert.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| P | Known part | number | The slice you already have, such as the tax component of a total. |
| W | The whole you are solving for | number | Always larger than the part when the percentage is under 100 — a useful sanity check. |
What Each Symbol Means
Pnumber
Known part
The slice you already have, such as the tax component of a total.
Wnumber
The whole you are solving for
Always larger than the part when the percentage is under 100 — a useful sanity check.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate a percentage 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 Calculate A Percentage, filed under Math. Every number the guide produces comes from substituting into this one line.