Understanding Percentage of a Percentage
A percentage of a percentage is a common concept that arises when you need to find a fraction of a fraction. For example, "What is 20% of 50%?" means you are taking 20% of the value that represents 50% of something. This type of calculation appears frequently in business discounts, tax calculations, and probability.
The Formula
To find a percentage of a percentage, convert both percentages to decimals and multiply them together, then convert back to a percentage:
Basic Formula
Multiply the two percentages as decimals, then express as a percentage.
Simplified Formula
Equivalently, multiply the two percentages and divide by 100.
With a Base Value
Apply the combined percentage to a base value.
Real-World Examples
Stacked Discounts
A store offers 30% off, and you have an additional 20% coupon applied after the first discount. The total discount is not 50%, but rather: 30% of the original is removed first, then 20% of the remaining 70% is removed. The extra discount is 20% of 70% = 14%. So the total discount is 30% + 14% = 44%, not 50%.
Commission Splits
An agent earns 15% commission, and shares 40% of that with their team. The team gets 40% of 15% = 6% of the total sale. The agent keeps 15% - 6% = 9%.
Key Points
- Percentage of a percentage always yields a smaller percentage than either input.
- The order does not matter: 20% of 50% equals 50% of 20%.
- This operation is multiplication, not addition.
- It is commonly confused with adding percentages, which gives incorrect results.