FAQ
How do I work out X% of Y?
Turn the percent into a fraction of 100 and multiply by Y. For example, 20% of 150 = 150 × (20 ÷ 100) = 30.
How do I work out an increase or decrease?
To increase, use Y × (1 + X ÷ 100). To decrease, use Y × (1 - X ÷ 100). X is the percent and Y is the original number.
What is the difference between % and “points”?
When 10% goes up to 12%, you can say “up 2 points”. You can also say “20% higher than before”, because 12 is 20% bigger than 10.
Which number is used as the starting value?
This calculator always treats Y as the starting value. If you change which number you use as the starting value, the answer in percent will also change.
What does “percent” mean in simple words?
Percent means “out of 100”. For example, 1% is 1 out of 100, 10% is 10 out of 100, and 25% is 25 out of 100. You can turn a percent into a decimal by dividing by 100.
When is this calculator useful?
It is handy for things like sale prices (for example, 30% off a price), test scores (for example, 40 out of 50 as a percent), or the share of a group (for example, how many students in a class). Even if you do not like formulas, you can just type numbers into X and Y and let the calculator do the work.