What this is
A percentage calculator with four separate modes. Each mode answers one common question, so you do not have to remember which number goes where.
The modes cover a percentage of a number, one number as a percentage of another, the change between two numbers, and a value adjusted up or down by a percentage. Results update as you type, and nothing is sent anywhere.
Where this is useful
Checking a sale price. Enter the original price and the discount to see both the amount saved and the final price.
Splitting a bill with a tip. Add a percentage to the total and read the new amount.
Tracking growth. Compare last month to this month and get the percentage change, including a decrease shown as a negative number.
Grading and weighting. Turn a raw score such as 43 out of 50 into a percentage.
Reading a budget. Find out what share one line item takes of the full total.
How to use this tool
Pick the mode that matches your question using the buttons at the top.
Fill in the two numbers the mode asks for. Decimals and negative numbers are both accepted.
Read the result below. The main figure appears in the large card, with the supporting numbers next to it.
Use the copy button to put the result on your clipboard, or clear the fields to start again.
Frequently asked questions
What is the difference between percentage change and percentage difference? Percentage change compares a new value against a starting value, so the order matters and the result can be negative. This tool calculates percentage change. Going from 50 to 75 is a 50 percent increase, while going from 75 to 50 is a 33.33 percent decrease.
How many decimal places do the results show? Results are rounded to two decimal places, and trailing zeros are dropped. The underlying calculation uses the full value, so rounding only affects what you read.
Why does the percentage change mode show a dash? Percentage change cannot be calculated from a starting value of zero, because any increase from zero is undefined as a percentage. Enter a non-zero starting value to get a result.
Are my numbers stored anywhere? No. Everything runs in your browser, and the numbers you enter are never sent to a server.