What is X% of Y?
% of
=
50
X is what percent of Y?
is
25%
of
Percentage Change
Percent Change
Change
+25%
Direction
📈 Increase
Absolute Diff
+20
Increase / Decrease a Value by X%
Result
Result
600
Change Amount
+100
X is Y% of what number?
is
% of
150
Percentage Formulas
| Calculation | Formula | Example |
|---|---|---|
| X% of Y | (X / 100) × Y | 20% of 250 = 50 |
| X is what % of Y | (X / Y) × 100 | 50 / 200 × 100 = 25% |
| % change A to B | ((B−A) / |A|) × 100 | (100−80)/80 × 100 = 25% |
| Y + X% | Y × (1 + X/100) | 500 × 1.20 = 600 |
| Y − X% | Y × (1 − X/100) | 500 × 0.80 = 400 |
| X = Y% of ? | (X / Y) × 100 | 45 / 0.30 = 150 |
Frequently Asked Questions
To find X% of Y: multiply Y by X, then divide by 100. Example: 20% of 150 = (150 × 20) ÷ 100 = 30. Or simply move the decimal: 20% of 150 = 0.20 × 150 = 30.
Percentage change = ((New − Old) ÷ Old) × 100. A positive result is an increase, negative is a decrease. Example: price rises from $80 to $100 → ((100−80) ÷ 80) × 100 = +25%.
Divide X by Y and multiply by 100. Example: 30 is what percent of 150? → (30 ÷ 150) × 100 = 20%.
Divide the final amount by (1 + percentage/100). Example: a price is $120 after a 20% increase → original = 120 ÷ 1.20 = $100.
Percentage points are an absolute difference between two percentages. If interest rates rise from 3% to 5%, that's a 2 percentage point increase — but a 66.7% relative increase. The two terms are often confused in financial news.