How do I find a percentage of a number?

Multiply the number by the percentage and divide by 100. 15% of 1,000 is 1,000 x 15 / 100 = 150.

How do I add or remove a percentage?

Add the percentage amount to the base to increase it, or subtract it to decrease it. 1,000 increased by 15% is 1,150; decreased by 15% it is 850.

Why is a rise then a fall not back to the start?

Because each percentage is taken on a different base. A rise of 15% then a fall of 15% leaves slightly less than you started with, since the fall is measured on the larger figure.

Can I use negative numbers?

Yes. A negative percentage decreases the base and a negative base reverses the direction, so the calculator handles both without a mode switch.

Is this a tax calculator?

No. It is plain arithmetic. For GST or income tax use the dedicated calculators, which apply the correct base and split.

General

Percentage Calculator

Percent of, increase and decrease.

Live resultNothing storedFormula shown

Your inputs

Base value1,000

Percentage(%)15%

Live result

Percentage amount

150

Base + percentage

1,150

Base − percentage: 850

Illustrative only — nothing you type is stored or sent anywhere. Confirm figures with the relevant authority before you rely on them.

When to use

When this applies

You want a percentage of an amount, and the amount with it added or removed.
You are applying a discount or a surcharge to a price.
You are checking a percentage figure in a report or a bill.
You are working out a change between two values.

Worked example

15% of 1,000

1Base 1,000, percentage 15.
2Percentage amount = 1,000 x 15 / 100 = 150.
3Base plus percentage = 1,000 + 150 = 1,150.
4Base minus percentage = 1,000 - 150 = 850.

15% of 1,000 is 150, giving 1,150 when added and 850 when removed.

Overview

What this calculator does

A quick percentage calculator: the percentage amount of a base value, the value after adding it and the value after subtracting it, all at once.

Method

How this is calculated

The percentage amount is the base multiplied by the percentage divided by 100. The increased value is the base plus that amount and the decreased value is the base minus it. The base and the percentage can both be negative, so the same calculator handles a discount and a surcharge without a separate mode.

Maths

The formula

Value = base × percent ÷ 100

Avoid

Common mistakes to avoid

Adding a rise and a fall of the same percentage
They do not cancel, because each is taken on a different base. The result is slightly below the starting figure.
Using the percentage on the wrong base
A percentage of the total and a percentage of the base are different numbers. Be clear which you are applying.
Treating it as a tax tool
Taxes such as GST are applied to a specific base with a specific split. Use the dedicated calculator rather than plain percentage arithmetic.

Answers

Frequently asked

How do I find a percentage of a number?: Multiply the number by the percentage and divide by 100. 15% of 1,000 is 1,000 x 15 / 100 = 150.
How do I add or remove a percentage?: Add the percentage amount to the base to increase it, or subtract it to decrease it. 1,000 increased by 15% is 1,150; decreased by 15% it is 850.
Why is a rise then a fall not back to the start?: Because each percentage is taken on a different base. A rise of 15% then a fall of 15% leaves slightly less than you started with, since the fall is measured on the larger figure.
Can I use negative numbers?: Yes. A negative percentage decreases the base and a negative base reverses the direction, so the calculator handles both without a mode switch.
Is this a tax calculator?: No. It is plain arithmetic. For GST or income tax use the dedicated calculators, which apply the correct base and split.

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