How to Calculate Percentages
Percentages are reversible. For example, 20% of 50 is the same answer as 50% of 20 (both equal 10). Our calculator handles the three most common percentage problems:
1. Find the Percentage of a Number
Formula: (P / 100) × N
To find 20% of 150, convert the percentage to a decimal (0.20) and multiply it by the number.
Example: 0.20 × 150 = 30
2. Reverse Percentage (What % is X of Y?)
Formula: (Part / Total) × 100
If you scored 45 out of 60 on a test, divide 45 by 60 to get 0.75, then multiply by 100 to get 75%.
3. Percentage Change (Increase or Decrease)
Formula: ((New Price - Old Price) / Old Price) × 100
If a price goes from $50 to $80, the difference is $30. Divide $30 by the old price ($50) to get 0.60, which is a 60% increase.