NerdBible
Sign in

Tools

More
All toolsAudioCalculatorsColour & CSSDeveloperEverydayHardware TestsImagePDF & DocumentsSecurity & PrivacyTextWeb & Marketing
More
ConcreteDatesGravel & soilPercentPower costPower runtimeRenewalsSolar sizeSquare feetSubscriptionsTilesTime zonesTip splitUnit priceUnits

Percentage Calculator

Percentages, changes, differences, discounts and VAT.

Free tools that run in your browser. Nothing you type, open or create is uploaded to NerdBible or anyone else.

What is X% of Y?

X is what percent of Y?

Percentage change from X to Y

Percentage difference between two values

Increase or decrease by a percentage

Discount: price after a percentage off

Reverse a percentage: the price before tax or a discount

Margin and markup

Results are rounded to six decimal places for display; copy takes the same rounded figure. Margin is profit as a share of the selling price, markup is profit as a share of the cost.

How to use it

  1. Find the question that matches yours, for example What is X% of Y, Percentage change, Percentage difference or Discount.
  2. Type your numbers into that card. The answer and the working appear straight away.
  3. Press Copy to take the answer. To get the price before VAT, use Reverse a percentage with Added; to undo a discount, choose Taken off.

Questions

How do I work out a percentage of a number?

Multiply the number by the percentage and divide by 100. 25% of 80 is 80 × 25 ÷ 100, which is 20.

How do I remove VAT from a price?

Divide the price by 1 plus the VAT rate. With 20% VAT, a price of 120 was 120 ÷ 1.2 = 100 before tax. Taking 20% off 120 gives 96, which is wrong, and is a common mistake.

What is the difference between margin and markup?

Both use the same profit. Margin divides it by the selling price, markup divides it by the cost. Buying at 60 and selling at 100 is a 40% margin and a 66.67% markup.

How do I work out a discount?

Multiply the price by the percentage off and divide by 100 to get the saving, then take the saving away from the price. 25% off 80 saves 20, so you pay 60. The Discount card shows both figures.

What is the difference between percentage change and percentage difference?

Percentage change has a direction: it measures from a starting value to a new one, so 80 to 100 is a 25% increase. Percentage difference compares two values with neither as the start: it divides the gap by their average, so 80 and 100 differ by 22.22% whichever way round you enter them.

Is a percentage change the same as percentage points?

No. Going from 10% to 15% is a rise of 5 percentage points but a 50% increase. The change card gives the percentage change.

About this tool

About the percentage calculator

Percentages turn up everywhere, from discounts and pay rises to tax and test scores, and the question is usually phrased in one of a handful of ways. Each card on this page answers one of them, showing the result and the working as you type.

Questions it answers

  • What is X% of Y?
  • X is what percentage of Y?
  • What is the percentage change from X to Y?
  • What is the percentage difference between two values?
  • Increase or decrease a number by a percentage.
  • Discount: the price after a percentage off, and how much you save.
  • Reverse a percentage: the original price before VAT was added or before a discount was taken off.
  • Margin and markup from a cost and a selling price.

Mistakes it helps avoid

Change versus difference: change runs from a starting value, so 80 to 100 is a 25% increase. Difference has no starting point: it divides the gap by the average of the two values, so 80 and 100 differ by 22.22% either way round.

Removing VAT: divide by 1 plus the rate. With 20% VAT, 120 was 120 divided by 1.2, which is 100. Taking 20% off 120 gives 96, which is wrong.

Margin versus markup: both use the same profit. Margin divides it by the selling price, markup by the cost.

Points versus percent: going from 10% to 15% is a rise of 5 percentage points, but a 50% increase.

Results are rounded to six decimal places for display. Everything is calculated in your browser.

Related tools