Percentage Calculator

A percentage is simply a way of expressing a number as a fraction of 100. The word comes from the Latin per centum, meaning "by the hundred." Saying 25% is the same as saying 25 out of 100, or the fraction 1/4, or the decimal 0.25. Because percentages put everything on the same 0-to-100 scale, they make it easy to compare quantities that would otherwise be hard to weigh against each other.

There are three percentage calculations people need most. The first is finding a percentage of a number — for example, a 20% tip on a $60 bill, which is 0.20 × 60 = $12. The second is working out what percentage one number is of another — if you scored 42 out of 50 on a test, that's 42 ÷ 50 × 100 = 84%. The third is percentage change, which measures how much a value has grown or shrunk: the difference between the old and new value, divided by the old value, times 100. A price that rises from $80 to $100 has increased by (100 − 80) ÷ 80 × 100 = 25%.

Percentages are everywhere in personal finance: interest rates, investment returns, inflation, sales tax, discounts, raises, and loan terms are all expressed as percentages. A common point of confusion is the difference between a percentage and a percentage point — if an interest rate rises from 4% to 6%, that's an increase of 2 percentage points but a 50% increase in the rate itself. Knowing which one is meant can change the meaning entirely.

This calculator removes the mental arithmetic so you can get a reliable answer in seconds, whether you're splitting a bill, checking a discount, or measuring how far a number has moved.