What is X% of Y?
What is% of?
X is what percent of Y?
is what percent of?
Percentage increase or decrease
Fromto
Add or subtract a percentage
increased or decreased by%
X is Y% of what number?
is% of what number?
Your numbers are used only in your browser. They are never sent anywhere or stored.
How to use the percentage calculator
- Find the box that matches your question, such as “What is X% of Y?” or “Percentage increase or decrease”.
- Type your numbers into the two fields.
- The answer appears as you type, with a short line showing how it was worked out.
Percentage formulas
- X% of Y = X ÷ 100 × Y. For example, 15% of 200 is 30.
- X is what percent of Y = X ÷ Y × 100. For example, 30 is 15% of 200.
- Percentage change = (new value − old value) ÷ old value × 100. For example, going from 80 to 100 is a 25% increase.
- Increase or decrease by X% = number × (1 ± X ÷ 100). For example, 120 increased by 15% is 138.
- X is Y% of what number = X ÷ (Y ÷ 100). For example, 45 is 30% of 150.
Good to know
- A percentage change cannot start from zero. Any change from 0 is infinite in percentage terms, so the calculator asks for a different starting value.
- Increases and decreases are not symmetric. A 50% increase followed by a 50% decrease does not return to the start: 100 becomes 150, then 75.
- Percentage points are different from percent. Going from 10% to 12% is a rise of 2 percentage points, but a 20% increase.
- Results are rounded to at most 6 decimal places. You can type numbers with commas, such as 1,250.
Is it private?
Yes. Every calculation happens in your web browser. The numbers you enter are never uploaded or stored, and this tool needs no outside libraries.