Percentage Calculator

Calculate percentages three ways: what is X% of Y, X is what percent of Y, and percentage increase or decrease between two numbers.

What is X% of Y?

% of =

X is what percent of Y?

is ? of

Percentage change from X to Y

→ =

The three percentage questions

Almost every real-world percentage problem is one of three shapes. "What is 15% of 80?" — multiply: 80 × 0.15 = 12 (tips, discounts, tax). "12 is what percent of 80?" — divide: 12 ÷ 80 × 100 = 15% (test scores, proportions). "From 80 to 92 is what change?" — difference over the original: (92−80) ÷ 80 = +15% (price rises, growth rates). All three update live above as you type.

Frequently asked questions

Why is a 50% gain then 50% loss not break-even?

Because the percentages apply to different bases: 100 → 150 → 75. Percentage changes compound on the current value, not the original.