Percentage Calculator

A general percentage solver for the three most common questions: X% of Y, X is what percent of Y, and X is Y% of what number.

X (percent %)Y (value)Decimals

15% of 240

36.00

Formula(15 ÷ 100) × 240

InputsX = 15, Y = 240

Rounded to 2 decimals.

Results update as you type

What this calculator does

This solver answers the three core percentage questions. Pick a mode, type two numbers, and read the answer along with the formula and the substituted calculation. For change between two values use Percentage Increase, Decrease, or Difference; for shopping savings use Percent Off or Discount.

Formula

X% of Y: result = (X ÷ 100) × Y

X is what percent of Y: result = (X ÷ Y) × 100

X is Y% of what: result = X ÷ (Y ÷ 100)

Variable definitions

X — The first input — a percent, a part, or a known value depending on the mode.
Y — The second input — a whole, a base value, or a percent depending on the mode.
result — The computed answer for the chosen mode.

Step-by-step calculation

Pick the mode that matches your question.
Convert any percent value to a decimal by dividing by 100.
Apply the formula for the selected mode.
Multiply by 100 again if the answer itself is a percent.

Worked example

Three quick worked examples covering each mode:

15% of 240 → 0.15 × 240 = 36.
36 is what % of 240 → (36 ÷ 240) × 100 = 15%.
36 is 15% of what → 36 ÷ 0.15 = 240.

How to use this calculator

Choose one of the three modes above the inputs.
Enter both numbers. The result and substituted formula update as you type.
Use Copy or Share to send the result with the formula recap.

Common mistakes

Forgetting to divide by 100: 15% is 0.15, not 15, when multiplying.
Swapping part and whole: in mode 2, X is the part and Y is the whole. (36 of 240) ≠ (240 of 36).
Confusing percent with percentage point: going from 8% to 10% is a 2 percentage-point rise, but a 25% increase.

Frequently asked questions

›How do I find X% of a number?

Convert the percent to a decimal (divide by 100) and multiply. 15% of 240 = 0.15 × 240 = 36.

›How do I find what percent one number is of another?

Divide the part by the whole and multiply by 100. 36 is what percent of 240? → (36 ÷ 240) × 100 = 15%.

›How do I find the whole when I know a percent and a part?

Divide the part by the percent expressed as a decimal. 36 is 15% of what? → 36 ÷ 0.15 = 240.

›What is the difference between a percentage and a percentage point?

A percentage is relative (10% of 200 = 20). A percentage point is an absolute change between two percentages (from 8% to 10% is a 2-point increase, or a 25% increase).

›Can the percent be greater than 100?

Yes. 150% of 80 = 120. This calculator supports any non-negative percent and value.

›How is this different from Percent Off or Discount?

This is a general-purpose percentage solver. For sale prices and savings, use Percent Off or Discount. For comparing two values, use Percentage Difference, Increase, or Decrease.

›How is rounding handled?

Results display to 4 significant figures (or 2 decimals when useful). Internal math is full double precision.