Percentage Formulas — Quick Reference
- X% of Y: (X ÷ 100) × Y
- What % is X of Y: (X ÷ Y) × 100
- % change from A to B: ((B − A) ÷ A) × 100
- Add X% to Y: Y × (1 + X/100)
- Subtract X% from Y: Y × (1 − X/100)
Common Percentage Examples
- VAT at 20%: Price × 1.20 to add VAT; Price ÷ 1.20 to remove VAT from a VAT-inclusive price.
- Tip at 10%: Divide the bill by 10. Move the decimal left one place: £85 → £8.50 tip.
- Discount: 30% off £120 = 120 × 0.70 = £84.
- Interest rate increase: 3% to 5% is 2 percentage points, but a 66.7% relative change.
What is the difference between percentage point and percent change?
A percentage point is the arithmetic difference between two percentages (3% to 5% = 2 percentage points). Percent change is the relative change: (5-3)/3 × 100 = 66.7%. Always clarify which you mean in financial or statistical contexts.