Percentage Calculator

Five percentage calculations at once. Enter two numbers and see the percent of, the ratio between them, the change from one to the other, and the value after an increase or decrease.

First number (X)

Second number (Y)

Every result below updates as you type. Use whichever line answers your question.

25% of 200

50.00

25 is what % of 200

12.5%

Change from 25 to 200

700%

Increase

25 increased by 200%

75.00

25 decreased by 200%

-25.00

Difference

175.00

Absolute gap between X and Y

What it is:: A percentage calculator covering five common relationships at once.
What it calculates:: Percent of a number, ratio between two numbers, percentage change, and increases or decreases.

Assumptions

Percentage change uses the first number as the base.
A rise and a fall of the same percentage do not cancel out.
GST-inclusive prices must be divided, not reduced by the rate.

How it works

Percentage change uses the first number as the base, so going from 200 to 250 is a 25% increase while 250 to 200 is a 20% decrease. The base matters.

A discount followed by a tax is not a wash: applying -10% then +10% leaves you below where you started.

Formula

X% of Y = (X / 100) x Y; change = (Y - X) / |X| x 100

X: = first number
Y: = second number

Example calculation

X = 25, Y = 200

25% of 200: 50.00
25 is what percent of 200: 12.5%
Change from 25 to 200: 700%
25 increased by 200%: 75.00
25 decreased by 200%: -25.00

Frequently asked questions

Why is a 20% fall not undone by a 20% rise?

Because the second percentage applies to a smaller base. A 100 that falls 20% becomes 80, and 20% of 80 is only 16, taking you to 96.

How do I calculate a discount?

Use the decrease result: the price after a discount of that percentage. To find the discount amount alone, use percent of.

Can I use this for GST?

Yes. Use the increase result to add GST to a base price. To strip GST out of an inclusive price, divide by 1 plus the rate rather than subtracting the percentage.