The most common percentage calculations
- Sale price: price × (1 − discount ÷ 100). $50 at 30% off = $35.
- Increase: value × (1 + increase ÷ 100). $1,800 + 3% = $1,854.
- Share: A ÷ B × 100. 12 out of 80 = 15%.
Frequently asked questions
How do I calculate a percentage of a number?
Multiply the number by the percentage, then divide by 100: 15% of 80 = 80 × 15 ÷ 100 = 12.
How do I calculate a percentage change?
(final value − starting value) ÷ starting value × 100. From 80 to 100, the change is +25%.
Does a 20% decrease followed by a 20% increase bring you back to the start?
No: 100 drops to 80, then 80 + 20% = 96. Successive percentages multiply; they do not add up.
More Calculators tools
- Days between dates: Calendar days, weekdays and working days.
- Unit converter: Length, weight, volume, temperature, data, cooking…