01
Find a part of a number
What isof?
Calculators
Percentage Calculator
Find a percentage, compare values, or calculate a percentage change.
Fill in the numbers
Type numbers into the blanks. The answer appears as you go.
02
Find what percent one number is of another
is what percent of?
03
Find the percent increase or decrease
Change fromto
04
Find the percent difference
Difference betweenand
Choose the sentence that matches your question. Only fill in its two number boxes.
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What this tool helps you find
Choose the sentence that matches your problem and enter the two numbers you know. The calculator leaves each formula separate so you can see which result answers your question.
Formula
Part = (percentage ÷ 100) × whole. Percent = (part ÷ whole) × 100. Percent change = |new − start| ÷ |start| × 100, labeled increase or decrease. Percent difference = |A − B| ÷ ((|A| + |B|) ÷ 2) × 100.
Worked example
20% of 500 is (20 ÷ 100) × 500 = 100.
Common mistake
Percentage change uses the starting value as its base. Percent difference instead compares two values against their average, so the two answers can differ.
When to use it
Check a sale discount, compare two measurements, or see how much a value rose or fell.
Questions and answers
How do I find a percentage of a number?
Convert the percentage to a decimal by dividing by 100, then multiply by the number.
How do I calculate percentage change?
Subtract the original value from the new value, divide by the original, then multiply by 100. A negative result is a decrease.