Percentage Calculator
Four common percentage calculations, instant results.
What is X% of Y?
% of
Enter values above
X is what percent of Y?
is what % of
Enter values above
X is Y% of what?
is% of what?
Enter values above
Percentage change from Old to New
→
Enter values above
Worked Example
Three common percentage questions answered:
What is 15% of £420?
£63.00
420 × 0.15 = 63
45 is what % of 300?
15%
45 ÷ 300 × 100 = 15
63 is 18% of what?
350
63 ÷ 0.18 = 350
How it's calculated
- What is X% of Y
- Result = X ÷ 100 × Y
- X is what % of Y
- Percent = X ÷ Y × 100
- X is Y% of what
- Whole = X ÷ (Y ÷ 100)
- % change
- Change = (New − Old) ÷ |Old| × 100
A percent is just a fraction of 100, so 15% means 15 ÷ 100 = 0.15. Multiplying by that decimal gives the share of a number.
Percentage change compares the difference to the starting value, which is why going from 50 to 100 is +100% but going back from 100 to 50 is −50%.
Frequently asked questions
You might also find useful