Percentage Calculator

Find X% of a number, what percent one number is of another, the percent increase or decrease between two values, and add or subtract a percentage. Every answer updates as you type.

The 5 percentage questions this calculator answers

Question	Formula	Example
What is X% of Y?	X / 100 x Y	20% of 150 = 30
X is what % of Y?	X / Y x 100	30 is 20% of 150
% change from X to Y	(Y – X) / X x 100	50 to 65 = +30%
Y increased by X%	Y x (1 + X / 100)	150 + 20% = 180
Y decreased by X%	Y x (1 – X / 100)	150 – 20% = 120

How to calculate a percentage in your head

Move the decimal one place to get 10%, then build from there. 10% of 85 is 8.5, so 20% is 17 and 5% is 4.25. To find 15% of a $60 bill, add 10% ($6) and half of it ($3): $9.

Percentages are also reversible: 8% of 50 is the same as 50% of 8, which is 4. Use whichever is easier.

Percent change vs. percentage points

If an interest rate goes from 4% to 5%, it rose by 1 percentage point, but by 25 percent (1 / 4 x 100). News stories mix these up all the time. The calculator’s “% change” mode gives the relative change.

Why a 50% loss needs a 100% gain

Percent increases and decreases are not symmetrical. If a $100 investment falls 50% to $50, it has to rise 100% to get back to $100. A price that goes up 10% and then down 10% ends 1% lower than where it started.

FAQ

How do I calculate a percentage of a total?

Divide the part by the total and multiply by 100. If you scored 42 out of 50, that is 42 / 50 x 100 = 84%.

How do I calculate percent increase?

Subtract the old value from the new value, divide by the old value and multiply by 100. Rent going from $1,500 to $1,620 is a (120 / 1,500) x 100 = 8% increase.

How do I add a percentage to a number?

Multiply by 1 plus the percentage as a decimal. $80 plus 15% is $80 x 1.15 = $92.

How do I find the original number before a percentage was added?

Divide by 1 plus the percentage. If $92 includes a 15% markup, the original was $92 / 1.15 = $80.