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Percentage Calculator

What is X% of Y, percent change and more, with the working

  • Runs in your browser
  • No sign-up
  • Free forever
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How to use the Percentage Calculator

  1. 1

    Find the question that matches yours, for example "What is 15% of 240?" or "Change from 80 to 100".

  2. 2

    Type your numbers into the boxes inside that sentence. The answer appears as you type.

  3. 3

    Read the line under each answer to see exactly how it was worked out.

  4. 4

    Click an answer to copy it, or press Copy link to share a link that reopens the page with your numbers.

  5. 5

    Press Reset to put every calculator back to its example values.

Features

  • Eight calculators on one page, each written as a plain sentence
  • Covers X% of Y, X as a percent of Y, finding the whole, percentage change, increase, decrease and percentage difference
  • Percentage points compared with relative percent, the difference most reports get wrong
  • The working shown under every answer, so you can check or reuse the method
  • Increase or decrease wording with colour for percentage change
  • Accepts commas or dots as decimals, for example 12,5 or 12.5
  • Clear messages instead of errors when a calculation would divide by zero
  • Copy link shares the exact numbers; nothing is sent to a server

Percentages in one place

Most percentage questions are one of a handful of patterns: a share of a number, one number as a share of another, a change between two values, or an adjustment up or down by a rate. This page lays each pattern out as a sentence with the numbers in it, so you pick the one that reads like your question and fill in the blanks. Every answer comes with the working, which makes it easy to check or copy into a spreadsheet.

The formulas

QuestionFormula
What is X% of YX ÷ 100 × Y
X is what % of YX ÷ Y × 100
X is Y% of whatX ÷ (Y ÷ 100)
Change from A to B(B − A) ÷ absolute value of A × 100
Increase Y by X%Y × (1 + X ÷ 100)
Decrease Y by X%Y × (1 − X ÷ 100)
Difference between A and Bgap between A and B ÷ their average × 100

Percentage change divides by the absolute value of the starting number, so a move from −50 to −25 reads as a 50% increase, which matches how accountants describe a shrinking loss.

To split a bill and add a tip, use the Tip Calculator. For loan repayments and interest, the Loan and EMI Calculator shows the full schedule.

Frequently asked questions

How do I calculate a percentage of a number?
Divide the percentage by 100 and multiply by the number. 15% of 240 is 15 ÷ 100 × 240 = 36. The first calculator on this page does this and shows the working underneath.
How do I work out percentage change?
Subtract the old value from the new one, divide by the old value and multiply by 100. From 80 to 100 is (100 − 80) ÷ 80 × 100 = 25%, an increase. A negative result is a decrease. A change from zero is undefined, because you cannot divide by zero.
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 +25% while 100 to 80 is −20%. Percentage difference compares two values without a starting point by dividing the gap by their average, so 120 and 150 differ by 22.2% whichever way round you enter them.
What are percentage points?
Percentage points measure the gap between two percentages by subtraction. An interest rate rising from 4% to 5% has gone up by 1 percentage point, which is a 25% relative increase. Both numbers are correct; they answer different questions, and the last calculator shows both.
How do I reverse a percentage increase?
Divide by one plus the rate rather than subtracting the percentage. A price of 108 after an 8% rise was 108 ÷ 1.08 = 100, while taking 8% off 108 gives 99.36, which is wrong. Use the X is Y% of what calculator with X = 108 and Y = 108 to get 100.
Are my numbers stored or sent anywhere?
No. The calculations run in your browser. Your last numbers are remembered on this device only. Copy link builds a link containing them, so they leave your browser only if you share it.

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