Percentage Calculator
Calculate percentages: percent of a value, percent change, or apply a percentage increase/decrease.
About Percentage Calculator
Percentage Calculator covers the three percent questions people actually ask: what is X percent of a value, what's the percent change between two numbers, and what do I get after applying an increase or decrease. It's the fast answer for discounts, tips, growth rates, and markups. It computes locally in your browser, so your figures stay private.
- Category
- create
- Input
- No file input — params only.
- Output
- Outputs: application/json.
- Cost
- Free, runs in your browser
- Memory
- low
Common uses
- Work out 20% off a list price to check a sale before buying
- Calculate the percent change between last month's and this month's revenue
- Apply a 15% tip to a bill total and see the new amount
- Find what percentage one test score is of the maximum possible
- Add a markup percentage to a wholesale cost to set a retail price
- Compute a year-over-year growth rate from two figures for a quick report line
Frequently asked questions
What calculation modes are there?
Three: percent of a value, percent change between two values, and applying a percentage increase or decrease to a value.
Do I upload a file?
No. You enter the numbers directly; the tool creates its own input and calculates in your browser.
Are my numbers sent anywhere?
No. Everything runs locally on your device, so the values you enter stay private.
How is the answer returned?
As JSON, giving you a clean, readable result that's easy to copy or chain into another tool.
Can it handle decreases and negative changes?
Yes. Percent change handles both increases and decreases, and the increase/decrease mode accepts a negative-direction adjustment to subtract a percentage.
Keywords
- percentage
- percent
- calculator
- math
- ratio
- discount
- change