Percentage Calculator
A free tool for the three percentage questions people run into most — find a percentage, find a ratio as a percentage, or find a percentage change.
What is % of ?
is what percent of ?
What is the percentage change from to ?
FAQ
What is a percentage?
A percentage is a way of writing a number as a portion of 100, marked with the "%" symbol. If 25 out of 100 marbles in a jar are blue, that's 25% of the marbles — the percentage always describes a part relative to a whole of 100.
How do you work out a percentage?
Divide the part by the whole, then multiply by 100. For example, if 20 of 50 apples are red, divide 20 by 50 to get 0.4, then multiply by 100 to get 40%. The same formula — part ÷ whole × 100 — covers most percentage questions, just rearranged depending on which values you already know.
How do you calculate percentage increase or decrease?
Subtract the starting value from the new value, divide by the starting value, then multiply by 100. Going from 200 to 250 is a change of 50, so 50 ÷ 200 × 100 = 25% increase. A negative result means the value went down rather than up.
Where do percentages come up in everyday life?
Restaurant tips, sale discounts, exam scores, interest rates, pay raises, and tracking changes over time (like a stock price or a body-weight goal) are all percentage calculations in disguise — usually one of the three forms this tool covers.
About this calculator
This tool covers the three percentage calculations people need most often: finding a percentage of a number, finding what percentage one number is of another, and finding the percentage change between two values. No sign-up, no data stored — just enter numbers and the answer updates instantly.