Percentage calculator
Work out A% of B, what percent A is of B, the percentage change from A to B, and the difference between two percentages in points and relative terms. Results appear as you type.
What is A% of B?
Formula: B × A ÷ 100
A is what percent of B?
Formula: A ÷ B × 100
Percentage change from A to B
Formula: (B − A) ÷ |A| × 100 (change relative to the starting value)
Difference between two percentages: points vs relative
Point difference = B − A (percentage points). Relative change = (B − A) ÷ |A| × 100.
How to use
- Pick the calculation you need (there are four) and enter the numbers A and B. The formula is shown under each heading.
- The result appears as soon as both numbers are entered. Thousands separators such as 1,000 are accepted.
- For a percentage change, an increase is shown with "+" and a decrease with "-".
- For the difference between two percentages, a change such as 10% → 15% is shown both as "+5 percentage points" and as a relative change of "+50%".
Notes and limits
- Results are rounded to at most 6 decimal places, and trailing zeros are hidden.
- B cannot be 0 in "A is what percent of B", and A cannot be 0 in a percentage change, because both would divide by zero.
- In the difference between two percentages, a starting rate of 0% shows only the point difference, with a note that the relative change cannot be calculated.
- For sale prices and discounts, a dedicated discount calculator is easier to use.
How it works
A% of B = B × A ÷ 100. A as a percent of B = A ÷ B × 100. Percentage change = (B − A) ÷ |A| × 100.
Difference between two percentages: point difference = B − A (percentage points); relative change = (B − A) ÷ |A| × 100 (%). A rate going from 2% to 3% is up 1 percentage point, or 50% in relative terms.
The change is divided by the absolute value |A| so that the sign still shows the direction when the starting value is negative (−10 → −5 is a 50% increase).
Floating-point noise (such as 0.30000000000000004) is removed by rounding to 12 significant digits.
FAQ
What is the difference between a percent change and percentage points?
Percentage points are the plain difference between two rates; a percent change is relative to the starting value. Going from 10% to 15% is a rise of 5 percentage points, but a 50% increase. The fourth calculator shows both.
How do I calculate a price after a 30% discount?
Discounts have their own tool: the discount calculator gives the sale price and the discount amount, and works out the percent off from two prices.
Can I enter negative numbers and decimals?
Yes. Every field accepts negative numbers and decimals. An error or note is shown only when a calculation would divide by zero.
Are my numbers saved or sent anywhere?
No. The calculation runs in your browser, and nothing you enter is sent or stored.
Related guides
- How to create an invoice and save it as a PDFStep-by-step: fill in your details, line items, discount and tax, choose the document language and currency, check the preview and download a PDF.
Related tools
Last updated: