Percentage Calculator
Four quick calculators: a percentage of a number, what percent one number is of another, percentage change, and adding or subtracting a percentage.
What is P% of a number?
e.g. 15% of 200 = 30
X is what percent of Y?
e.g. 30 is 15% of 200
Percentage increase or decrease
e.g. from 200 to 250 is a 25% increase
Increase or decrease a number by a percentage
e.g. 200 increased by 15% = 230
Percentage formulas
- P% of X = X × P ÷ 100
- X as a % of Y = X ÷ Y × 100
- Percentage change = (new − old) ÷ old × 100
- X increased by P% = X × (1 + P ÷ 100), and decreased = X × (1 − P ÷ 100)
- Need the original number before a percentage was added or taken off? Use the Reverse Percentage Calculator.
Percentage Calculator: frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage and divide by 100. For example, 15% of 200 is 200 × 15 ÷ 100 = 30.
How do I find what percent one number is of another?
Divide the part by the total and multiply by 100. For example, 30 out of 200 is 30 ÷ 200 × 100 = 15%.
How do I calculate percentage increase or decrease?
Subtract the old value from the new value, divide by the old value and multiply by 100. From 200 to 250 is (250 − 200) ÷ 200 × 100 = a 25% increase.
How do I add a percentage to a number?
Multiply the number by (1 + percentage ÷ 100). For example, 200 plus 15% is 200 × 1.15 = 230. To subtract, multiply by (1 − percentage ÷ 100).
How do I calculate my exam percentage or marks percentage?
Use the "X is what percent of Y" calculator: enter the marks you got as the part and the maximum marks as the total. 450 out of 500 is 90%.