About this calculator
Percentages come up constantly — discounts, tips, tax, grades, growth. This calculator handles the three questions people ask most: a percentage of a number, one number as a percentage of another, and the percentage change from one value to the next. Pick a mode and the answer updates instantly.
How it works
Choose the mode that matches your question. "X% of Y" multiplies Y by X divided by 100. "X is what % of Y" divides X by Y and multiplies by 100. "% change" takes the difference between the two values, divides by the starting value, and multiplies by 100 — a positive result is an increase, a negative one a decrease.
Frequently asked questions
How do I find a percentage of a number?
Multiply the number by the percentage and divide by 100. For 20% of 80: 80 × 20 ÷ 100 = 16.
How do I work out a percentage change?
Subtract the old value from the new, divide by the old value, and multiply by 100. From 50 to 60 is a 20% increase.
What does a negative result mean?
In change mode, a negative percentage means a decrease — the value went down.
Can it handle decimals?
Yes, you can enter decimals in any field and the result adjusts accordingly.