Percentage Calculator — Free Online Percent Tool (No Sign-up)

How to use the percentage calculator

Pick the question that matches what you need. Each tab solves a different, very common percentage problem and updates the answer as you type.

Choose a mode: “X% of Y”, “X is what % of Y”, or percent increase / decrease.

Type your two numbers. The result appears instantly, with no button to press.

Read the highlighted result — for discounts, tips, tax, growth and more.

The three formulas explained

X% of Y = X ÷ 100 × Y. Example: 20% of 150 = 30.

X is what % of Y = X ÷ Y × 100. Example: 30 of 150 = 20%.

Percent change = (new − old) ÷ old × 100. Example: 100 → 125 = +25%.

Frequently asked questions

How do I calculate a percentage of a number?

Multiply the number by the percentage and divide by 100. For example, 15% of 80 is 80 × 15 ÷ 100 = 12.

How do I find the percent increase between two numbers?

Subtract the old value from the new value, divide by the old value, then multiply by 100. Going from 50 to 65 is (65 − 50) ÷ 50 × 100 = 30%.

What if the starting value is zero?

Percent change from zero is undefined (you cannot divide by zero), so the calculator will show a dash instead of a misleading number.

Is this percentage calculator free and private?

Yes. It's completely free, requires no account, and every calculation runs in your browser — nothing is sent to a server.