Percentages
How do you calculate a percentage of a number?
What is X% of Y, what percent is X of Y, percentage change between two numbers.
Quick answer
X% of Y = (X ÷ 100) × Y. Example: 20% of 150 = 0.20 × 150 = 30. To find what percent X is of Y: (X ÷ Y) × 100 — 30 is 20% of 150 because 30 ÷ 150 × 100 = 20%.
20% of 150
30
How it works
Percentage change from A to B = ((B − A) ÷ |A|) × 100. Price rising from 80 to 100 is a 25% increase (20 ÷ 80 × 100), not 20%. The calculator handles all three modes: of, what percent, and change.
Frequently asked questions
How do I add 20% to a price?+
Multiply by 1.20. €100 + 20% = €120. To remove included markup, divide by 1.20 — do not subtract 20%.
Percentage vs percentage points?+
Rate rising from 2% to 5% is +3 percentage points but +150% relative increase. Headlines often confuse the two.
How do I calculate a tip?+
Tip = bill × (percent ÷ 100). €45 at 15%: 45 × 0.15 = €6.75. Ten percent is bill ÷ 10.
Can percentages exceed 100%?+
Yes when comparing to a smaller base. Revenue doubling is +100%; tripling is +200%.
As an Amazon Associate I earn from qualifying purchases — the price does not change for you.