Comprehensive Calculator Guide
This calculator works out a percentage of another percentage. 20% of 50% is 10%, and 30% of 40% is 12%. Add an amount and it applies the result directly: 30% of 40% of 1,500 students is 180. It also flags a common mistake: 40% off followed by 30% off isn’t 70% off, but 58%.
Shares of shares and stacked discounts
Multiply the two percentages and divide by 100, or multiply them as decimals: 0.3 × 0.4 = 0.12 = 12%. It’s how you find a group within a group, such as science-track students within a school’s secondary students.
With two discounts, the second applies to what’s left: 40% then 30% is 40% + 18% = 58%. In general, total = 100% − (100% − first) × (100% − second) ÷ 100.
How to Use
- Enter the first percentage — the part you’re taking.
- Enter the second percentage, and an amount if you like.
- Press “Calculate” to see the result, its value on the amount and the stacked discount.
Formula Used
a% of b% = (a × b) ÷ 100 %
Practical Examples
- Example 1
- 20% of 50% = 10%.
- Example 2
- 30% of 40% = 12%; of 1,500 that’s 180.
Important Tips
- A percentage of a percentage under 100% is always smaller than both.
Common Mistakes to Avoid
- Adding the percentages instead of multiplying.
Frequently Asked Questions
- How do I calculate a percentage of a percentage?
- Multiply them and divide by 100.
- Is 50% off then 20% off the same as 70% off?
- No, it’s 60%.
- What is 30% of 40% of 1,500?
- 12% of 1,500, which is 180.