Percentage Calculator
Work out any percentage — of a number, as a ratio, or as a change.
What is X% of Y?
What is% of
Result—
X is what percent of Y?
is what percent of
Result—
Percentage change from X to Y
Fromto
Result—
This percentage calculator handles the three questions people actually ask: what a given percentage of a number is, what percentage one number represents of another, and how much a value has changed in percentage terms. Type into any row and the answer updates instantly, so there is no submit button to press.
Every calculation runs locally in your browser — nothing you enter is uploaded or stored. It works with decimals and negative numbers, making it handy for discounts, tax, tips, grades, growth rates, and any quick everyday math.
How to use
- For "what is X% of Y", enter the percentage in the first box and the number in the second; the result appears below.
- For "X is what percent of Y", enter the part first and the whole second to get the ratio as a percentage.
- For percentage change, enter the starting value and the ending value to see the increase or decrease.
- Read the result under each row — a positive change shows a plus sign and is labelled increase, a negative one is labelled decrease.
FAQ
- How is percentage change calculated?
- Percentage change is (new value − old value) ÷ old value × 100. A rise from 200 to 250 is (250 − 200) ÷ 200 × 100 = 25% increase.
- What is the difference between percentage points and percent?
- Percentage points measure the absolute gap between two percentages, while percent measures relative change. Going from 10% to 15% is a rise of 5 percentage points but a 50% increase.
- Can I use decimals and negative numbers?
- Yes. You can enter values like 12.5 or −30, which is useful for discounts, refunds, and figures that drop below zero.
- Why does the change field show a dash?
- The change is undefined when the starting value is zero, because you cannot divide by zero. Enter a non-zero starting value to see a result.
- Is my data sent anywhere?
- No. All three calculators run in your browser with JavaScript. The numbers you type are never transmitted, saved, or shared.