Percentage Calculator

Find what P% of a number is, what percent one number is of another, or the whole from a part.

%
Answer
12
Part of the whole
Part: 12 (15%)Rest: 68 (85%)15%of the whole
  • Part1215%
  • Rest6885%
Show the working
  1. 15% × 80 = 15 ÷ 100 × 80
  2. = 12

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Formula

P% of X = (P ÷ 100) × XY as a % of X = (Y ÷ X) × 100Whole = Y ÷ (P ÷ 100)

How it works

A percentage is a fraction with 100 as its denominator: "15 percent" literally means 15 per hundred. That is why every percentage problem comes down to multiplying or dividing by 100.

Pick the question that matches yours. The calculator only needs the two numbers that question uses, and shows the arithmetic so you can check it by hand.

Frequently asked questions

How do I calculate 20% of a number in my head?

Find 10% by moving the decimal point one place left, then double it. 20% of 85 is 8.5 × 2 = 17.

Is X% of Y the same as Y% of X?

Yes. Multiplication is commutative, so 8% of 50 equals 50% of 8 — both are 4. This trick often makes mental math easier.

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