- Education and Science
How to Calculate Percentages - Calculating Percentages Easily
Calculating and working out percentages made easy!
Percentages really aren't that difficult, yet they are so useful and so many people cannot easily work them out! This lens shows you how to work out a percentage so you'd never need worry at school or work again!
Below is first of all how to calculate a basic percentage. Then there is the slightly more complicated calculations - calculating increase and decrease, then decreasing a number by a percentage.
So without further ado...here's how to calculate and work out percentages!
Working out the percentage of a number
Lets say were working out 30% of $40. You must understand that 30% is equilivant to 30/100, and also to 0.3.
- So we multiply $40 * 30/100 = $12
Remember 30% and 30/100 is the same as 0.3
Alternatively, you can simply divide the amount (in this case $40) by 100 to get 1%, and then multiply it by the percentage of the amount you require e.g:
- $40/100= 0.4
Then multiply 0.4 by 30%:
- 0.4*30 = $12
Use which ever way is easiest for you to remember, I prefer the second way!
And that's it, How to calculate percentages!
Calculating a Percentage Increase
How to work out the percentage a number has increased by
If price increases from $50 to $54. What is the % increase?
Firstly, we need to know the difference, in this case its $4:
- $54-$50 = $4
Then divide the difference (54-50) by the initial amount.
- So it is 4 / 50 = 0.08
Then simply multiply to get a nice percentage:
- 0.08 * 100 = 8%
Increasing and Decreasing a Number by a Percentage
Working out the amount to increase or decrease a number by
Say you work in a shop and you know that you sold 10,000 items this year and your boss says he wants to see a 20 percent increase next year. How much do you need to sell next year?
I find the quickest way to do this is multiply the amount, in this case 10,000 by 1.2 (the .2 is the 20%) so:
- 10,000*1.2 = 12,000
You can do this backwards as well to calculate a decrease. To calculate a 20% decrease simply imagine 1 as 100%. So take 20% off 100% and you get 80%, or 0.8.
- 10,000*0.8 = 8,000
Or we could find 20% of 10,000 and then add it to 10,000:
- 20/100 (0.2) * 10000 = 2000