Percentage of Number Calculator

Answer “what is 15% of 240?” or “45 is what percent of 200?” without mental gymnastics. Enter a percentage and a base, or read the second line as a ratio check.

Percent of a number

Percent (%)

Of this number

(Optional) This value is what % of base?

How this is calculated

Part = base × (percent ÷ 100). To express the base as a fraction of a larger whole, enter whole as the second number in your head: here we show percent of = 100 × (part ÷ whole) when you treat the first field as the “part”—see form labels.

Example: 15% of 240 = 36.

Use this tool for

Commissions, sales tax slices, or progress to a goal.
Checking homework on ratio word problems.
Back-of-napkin data estimates in meetings.

Common questions

What if I only need “what percent is A of B”?

Set base = B and use the optional third field = A; the second phrase reports 100×A÷B.

Rounding?

Display uses your browser locale; verify critical figures to the precision your process requires.