Calculators

Percentage Calculator

Calculate what percent one number is of another, find a percentage of a value, and work out percentage increases or decreases.

Calculators · Percentage CalculatorRuns in your browser

What is X% of a number?

Percentage (%)

Of value

Result

X is what percent of Y?

Value (X)

Total (Y)

Result

20%

Percentage increase / decrease

From

Change

+25%

Percent off (discount)

Original price

Percent off (%)

Final price

You save

Add or subtract a percentage

Value

Adjust by (%) — use a minus to subtract

Result

220

How to use the percentage calculator

Find the section that matches your question: what is X% of a number, X is what percent of Y, percentage increase or decrease, percent off, or add and subtract a percentage.
Type your two numbers into that section's fields. Each section starts with example values, so you can simply overwrite them.
Read the result in the box under the fields. It recalculates on every keystroke, with no button to press.
In the discount section, note both figures: the final price and the amount you save.

Five calculations on one page

The sections are independent: typing in one of them never changes another. That makes it easy to cross-check a figure, for example confirming that a 25% discount on 80 leaves 60, then entering 20 and 80 in the second section to see that the saving really is 25% of the original price.

Section	Formula	Starting example
What is X% of a number?	percent ÷ 100 × value	20% of 150 = 30
X is what percent of Y?	X ÷ Y × 100	30 is 20% of 150
Percentage increase / decrease	(to − from) ÷ from × 100	100 → 125 is +25%
Percent off (discount)	price − price × percent ÷ 100	25% off 80 = 60, saving 20
Add or subtract a percentage	value × (1 + percent ÷ 100)	200 adjusted by +10% = 220

What each section computes, shown with the values it starts with.

Reading the increase / decrease result

The change box carries a sign: a plus for a rise and a minus for a fall. Put the earlier or original figure in From and the later figure in To, because the change is always measured against the From value. Going from 100 to 125 is +25%, but going back from 125 to 100 is −20%, since 25 is only a fifth of 125.

A From value of 0 produces a dash instead of a number, because a change from nothing has no percentage. A negative From value is allowed and the sign follows the direction of travel: the change is divided by the size of the starting figure, so from −50 to 50 shows +200%, and from −50 to −100 shows −100%. That is the convention accountants use for a loss turning into a profit.

Adding a markup, tax or raise with the last section

The Adjust by field accepts a minus sign, so one section handles both directions: 200 adjusted by −10 gives 180, and 200 adjusted by +10 gives 220. Typical uses are adding 20% VAT to a net price of 50 (result 60) or applying a 3.5% pay rise to 42,000 (result 43,470).

Removing a percentage that was previously added is not the mirror image. Taking 20% off 60 gives 48, not the 50 you started from, because the 20% is now taken from a bigger number. There is no reverse-percentage mode on this page, so to strip an added 20% divide by 1.2 instead: 60 ÷ 1.2 = 50.

How results are rounded

Every result is rounded to four decimal places and then formatted with your browser's number settings, which show at most three decimals and add thousands separators. One third as a percentage therefore appears as 33.333%, and 7 out of 9 appears as 77.778%. Inputs can be decimals, large numbers or negatives; anything that does not produce a finite number is shown as a dash.

Worked examples

Exam score: 43 marks out of 60. Second section, X = 43, Y = 60 → 71.667%.
Price rise: a laptop that cost 1,299 now costs 1,449. Third section, From 1,299, To 1,449 → +11.547%.
Sale price: 15% off a 64.00 jacket. Fourth section → final price 54.4, you save 9.6.
Tip-style markup: 200 adjusted by +10 in the last section → 220.
Share of a total: 30 is what percent of 150? → 20%, the second section's starting example.

Frequently asked questions

How do I calculate a percentage of a number?

Multiply the number by the percentage and divide by 100. For example, 20% of 150 is 150 × 20 ÷ 100 = 30.

Why does the result show a dash instead of a number?

A dash means the calculation did not produce a finite number: a field is empty, or you are dividing by zero, for example a Total (Y) of 0 or a From value of 0. Fill in or correct the field and the result appears.

How do I find the original price before a discount?

Divide the sale price by (1 − discount ÷ 100). A jacket that costs 60 after 25% off was 60 ÷ 0.75 = 80 originally. You can confirm it by entering 80 and 25 in the percent-off section, which returns 60.

What is the difference between percent change and percentage points?

If a rate moves from 40% to 45% it has risen by 5 percentage points, but the increase / decrease section reports the relative change, which is (45 − 40) ÷ 40 × 100 = +12.5%. Use points when both figures are already percentages of the same base.

Can I enter decimals and negative numbers?

Yes. Every field is a plain number input, so 12.5% of 99.99 or an adjustment of −7.25% work as expected. Negative values in the From field of the change section flip the sign of the result, so avoid them there.

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