Free

Percentage Calculator

To find a percentage of a number, multiply the number by the percentage and divide by 100: 15% of 200 = 200 × 15 ÷ 100 = 30. To find what percent one number is of another, divide the part by the whole and multiply by 100: 30 is 15% of 200. Percentage change is (New − Old) ÷ Old × 100. This tool handles all four calculations in separate sections and shows the result as you type.

Percentage of a number (Y% of X)

Result
—

X is what percent of Y?

Percentage
—

Percentage increase / decrease

Percentage change
—
Difference
—

Add / subtract a percentage

With percentage added
—
With percentage subtracted
—
Percentage amount
—

Your data never leaves your device: everything runs in your browser and nothing is sent to a server.

The tool opens after a quick security check…

How to use it

  1. 1In the first section, enter a number and a percentage to get Y% of X.
  2. 2In the second section, enter the part and the whole to see what percent the part is.
  3. 3In the third section, enter the old and new values to see the percentage increase or decrease and the difference.
  4. 4In the fourth section, enter an amount and a percentage to see the amount with the percentage added and subtracted.
  5. 5Use a dot for decimals (12.5); results are rounded to 2 decimal places.

Percentage formulas

  • Y% of X = X × Y ÷ 100
  • X as a percentage of Y = X ÷ Y × 100
  • Percentage change = (New − Old) ÷ Old × 100
  • Add a percentage = X × (1 + Y ÷ 100); subtract = X × (1 − Y ÷ 100)

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 450 is 450 × 20 ÷ 100 = 90. The first section of the tool does this for you.

How do I find a percentage increase or decrease?

Subtract the old value from the new one, divide by the old value and multiply by 100. Going from 80 to 100 is a 25% increase; going from 100 to 80 is a 20% decrease. The calculation is always based on the old (starting) value.

If a value rises 20% and then falls 20%, is it back where it started?

No. 100 rises 20% to 120; 20% of 120 is 24, so it then falls to 96. The increase and decrease use different bases, so they do not cancel out.

Is adding a percentage the same as adding the percentage amount?

Yes. Adding 18% to 1,000 gives 1,000 × 1.18 = 1,180, the same as adding 180 (18% of 1,000). Be careful in reverse: subtracting 18% from 1,180 gives 967.60, not 1,000.

Why is no percentage change shown when the old value is zero?

Percentage change divides by the old value, and division by zero is undefined, so no result is shown. In that case, use the absolute difference instead.

Related tools

VAT Calculator

Add VAT to a net amount or extract VAT from a gross amount; use 1%, 10%, 20% or a custom rate, with multiple lines showing net, VAT and total.

Profit Margin Calculator

Calculate profit, margin and markup from cost and selling price; find the price for a target margin and work out discounted and original prices.

Date Calculator

Calculate the days, weeks, months and business days between two dates, and add or subtract days from a date. Public holidays are not included.

Need custom software or a website for your business?

These tools are built by abcware. Let me build a website, web application or integration tailored to your quoting, inventory, order or customer processes.

Get a quote→