Percentage Calculator
Three quick percentage calculators. Results update as you type, and everything runs in your browser.
What is a percentage of a number?
A number is what percent of another?
Percent change between two numbers
How to calculate a percentage
- Pick the calculator that matches your question. There are three: “What is a percentage of a number?”, “A number is what percent of another?”, and “Percent change between two numbers”.
- For the first, enter the percent and the value: put in 15 and 200 to find 15% of 200. The result appears as you type.
- For the second, enter the number and the whole it belongs to, and it shows what percent the first is of the second.
- For percent change, put the earlier number in “From” and the later one in “To”. The result reads as an increase or a decrease.
When to use it
These are the everyday sums: a tip, a discount, sales tax, a test score, a share of a total. The three calculators are independent, so you can keep more than one on screen and work them at the same time.
Percent change is the one for comparing a before and an after: a price that moved, a metric quarter over quarter, a weight or a score. The direction word tells you at a glance whether the number went up or down, which a bare figure doesn’t.
Frequently asked questions
What can this calculator work out?
Three things: what X% of a value is, what percent one number is of another, and the percentage increase or decrease between two values. Each calculator works independently and updates as you type.
How is percentage change calculated?
As (new − old) ÷ old × 100. The result shows the magnitude with a direction word: increase, decrease, or no change.
Why do I get no result when the starting value is 0?
Percentage change from 0 is mathematically undefined, because there is no baseline to grow from. The same applies to asking what percent something is of 0.
How many decimal places are shown?
Results are shown with up to 4 decimal places, so long repeating decimals are trimmed rather than overflowing the line.
Are the numbers I enter sent anywhere?
No. Everything is computed instantly in your browser as you type. Nothing is uploaded or stored on a server.