How to Calculate Percentages
Hesaplayıcı1 min read
Short answer
To find a percentage of a number, multiply the number by the percentage and divide by 100: part = number × percent ÷ 100. For example, 12% of 250 is 250 × 12 ÷ 100 = 30. For an increase, add the part to the number; for a discount, subtract it. A 12% raise turns 250 into 280.
Formulas
- Part:
number × percent ÷ 100 - After an increase:
number + part - After a discount:
number − part
For example, a 25% discount on 800: 800 × 25 ÷ 100 = 200, so the result is 800 − 200 = 600.
Percentage change between two numbers
To find by what percentage a value changed, divide the difference by the old value and multiply by 100: (new − old) ÷ old × 100. A price that goes from 80 to 100 changes by (100 − 80) ÷ 80 × 100 = 25%. The percentage calculator does not do this; it gives a percentage of a number and the values after an increase and a discount.
Percent and percentage points
If an interest rate goes from 10% to 12%, it rises by 2 percentage points, but by (12 − 10) ÷ 10 × 100 = 20% in percent terms. Keep the two apart when you read about changes in rates.
A common mistake
A 20% raise followed by a 20% discount does not bring you back: 100 becomes 120, then 20% of 120, which is 24, comes off, and the result is 96. The second percentage applies to the new value.
Worked example: 20% of 1,000
Percentage of amount
200
- After increase
- 1,200
- After discount
- 800
Step by step
Percentage of amount
part = amount × percent / 100
part = 1,000 × 20 / 100 = 200