Step-by-Step Calculation
Finding X% of a number:
- Convert the percentage to a decimal (divide by 100).
- Multiply by the number.
Worked Example
What is 18% of 250?
18/100 = 0.18
0.18 × 250 = 45
Percentage increase example: A price rises from $80 to $92.
Change = 92−80 = 12. Percent increase = 12/80 × 100 = 15%
Frequently Asked Questions
How do I calculate percentage decrease?
Same formula as increase, but the change is negative: (new − old)/old × 100 — a negative result indicates a decrease.
How do I calculate what percentage one number is of another?
Divide the part by the whole, then multiply by 100 — for example, 30 out of 120 is (30/120)×100 = 25%.
