Percentages
Percentage of a number
Type one. Convert the percentage to a decimal by dividing by 100, then multiply by the base.
The Formula
Part = Whole x Percentage / 100
Type one. Convert the percentage to a decimal by dividing by 100, then multiply by the base.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| W | The whole or base amount | number | Whatever the percentage is being taken of. It always follows the word "of" in the sentence. |
| x | Percentage as a whole number | percent | 15 means fifteen percent, which becomes 0.15 in arithmetic. |
| P | The resulting part | number | Smaller than the whole for percentages under 100, equal for exactly 100. |
What Each Symbol Means
Wnumber
The whole or base amount
Whatever the percentage is being taken of. It always follows the word "of" in the sentence.
xpercent
Percentage as a whole number
15 means fifteen percent, which becomes 0.15 in arithmetic.
Pnumber
The resulting part
Smaller than the whole for percentages under 100, equal for exactly 100.
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.