Choose the percentage question that matches what you need. Every answer updates instantly as you type.
Enter a percentage and a number.
Find what percentage one value represents of another.
Compare the change with the starting value.
Y × (X ÷ 100)(X ÷ Y) × 100((new − old) ÷ old) × 100The first question finds a percentage of a known amount. The second finds what percentage one value represents of another. The third measures percentage increase or decrease relative to the starting value.
Percentage change is measured against the starting value. Moving from 100 to 125 is a 25% increase. Moving from 125 back to 100 is a 20% decrease because the starting value is different.
If the starting value is zero, a normal percentage-change calculation is undefined because the formula would require division by zero.
Use the first question. Enter 20 in the percentage field and the number you want to calculate from.
Use the second question. Divide the first number by the second, then multiply by 100.
Subtract the new value from the original value, divide by the original value, and multiply by 100.