Math Calculators
Percentage Calculator
Calculate percentages, percentage changes and values from a percentage.
Calculate percentages, changes, discounts and original values instantly. Calculations stay in your browser.
What is X% of Y?
X is what percent of Y?
Percentage change
Increase or decrease by %
Find original value
Percentage difference
Percentage calculation formulas
Percentage of a number: (percentage ÷ 100) × number.
Part as a percentage: (part ÷ total) × 100.
Percentage change: ((new − original) ÷ |original|) × 100. This convention uses the magnitude of the original as the reference for negative originals.
Increase/decrease: starting value × (1 ± percentage ÷ 100).
Reverse percentage: final value ÷ (1 ± percentage ÷ 100).
Percentage difference: |A − B| ÷ ((|A| + |B|) ÷ 2) × 100.
Frequently asked questions
How do I calculate 15% of 200?
Multiply 200 by 15 ÷ 100. The result is 30.
How can I reverse a discount?
Divide the discounted price by (1 − discount percentage ÷ 100). For example, 80 after a 20% discount means the original price was 100.
Is percentage change the same as percentage difference?
No. Percentage change measures the change relative to an original value; percentage difference compares two numbers symmetrically.
Are my numbers uploaded?
No. All calculations run locally in your browser.
How to use the Percentage Calculator
Enter the values in the calculator and choose the calculation you need. Results are calculated in your browser and are not sent to a server.
Percentage formula
To find p% of a value x, calculate (p ÷ 100) × x.
Example
20% of 150 is (20 ÷ 100) × 150 = 30.