Percentage Calculator

Five percentage questions. Fill the blanks, get the answer.

What is
Percent
of
Number
?
—
Part
is what % of
Whole
?
—
From
From
to
To
is a change of
—
Number
plus and minus
Percent
—
Part
is
Percent
of what?
—

Answers are rounded to 4 decimals. Copy gives the plain number. Nothing you type is stored or sent.

About

Five everyday percentage questions on one page: X% of a number, what percent one number is of another, the percent change between two numbers, a number plus and minus a percent, and the original number a percent came from. Fill the blanks in any row and the answer appears, with the working underneath so you can check it by hand.

How do I work out a percentage of a number?: Multiply the number by the percent and divide by 100. 20% of 150 is 150 x 20 / 100 = 30.
How do I calculate percent increase or decrease?: Take the difference, divide it by the starting number and multiply by 100. From 50 to 65 is (65 - 50) / 50 x 100 = 30%, an increase. From 80 to 60 is a 25% decrease.
Why doesn't adding 20% and then taking 20% off get me back?: Because the second 20% is of a bigger number. 100 plus 20% is 120, and 20% of 120 is 24, so you land on 96. To undo a rise, use the last row instead: 120 is 120% of 100.
How do I find the price before a discount?: If something costs 120 after 20% off, you paid 80% of the original. Put 120 and 80 in the last row: 120 is 80% of 150.
What about negative numbers?: They work in every row. For percent change the starting number counts by its size, so going from -50 to -25 is a 50% increase: the number went up. Some calculators call that a decrease; this one follows the direction the number moved.
What is the difference between a percent and a percentage point?: A rate going from 10% to 12% rose by 2 percentage points, but by 20 percent, because 2 is 20% of 10. Use the change row with 10 and 12 to get the second figure.