You may think percentage calculations are useful only if you use them for work. But in reality, they help you in everyday life. Do you know how to tip properly? Is this discount a real deal? How much will you pay with this interest rate? Come find the answers to these and other similar questions in this article.
Percent (or per centum from Latin) means one hundredth part. It is marked by a special sign: %, and represents a part of the whole.
For example, you and your 4 friends are getting a birthday gift for another friend. It costs $250 and you're chipping in together. How much should you give, percentage wise?
This is how you usually calculate percents:
Let's see: you're giving away $50. 50/250*100 - and you get 20% of the gift cost.
However, Google Sheets makes everything simpler since it calculates some parts for you. Though there is no unique formula for each and every case, there are some basic ones that will help you get different results depending on your task, whether calculating percentage change, percent increase, percentage of total, etc.
This is how Google spreadsheet calculates percentage:
Compared to the formula I mentioned previously, this one doesn't include multiplying by 100. And there's a good reason for that. Simply set the format of cells to percent and Google Sheets will do the rest.
So how will this work on your data? Imagine you keep track of ordered and delivered fruits (columns B and C respectively). To calculate the percentage of what's been delivered, do the following:
=C2/B2
Here's how the result looks on real data:
I removed all decimal places making the formula show a rounded percent of delivered fruits.
Here are a few more examples of calculating percentage of a total. Though the previous shows the same, it works great for that example but may not be enough for other data set. Let's see what else Google Sheets offers.
I believe this is the most common case: you have a table with values in column B. Their total resides at the very end of the data: B8. To find the percentage of the total for each fruit, use the same basic formula as before but with a slight difference - an absolute reference to the cell with the total sum:
=B2/$B$8
I also formatted the results as percent and left 2 decimals to display:
Now, suppose a fruit appears more than once in your table. You need to find what part of the total is composed by all orders of that fruit.
The SUMIF function will help:
It will sum only numbers belonging to the fruit of interest and divide the result by the total.
See for yourself: column A contains fruits, column B - orders for each fruit, B8 - the total of all orders. E1 has a drop-down list with all possible fruits where I chose to check the total for Prune. Here's the formula for this case:
=SUMIF(A2:A7,E1,B2:B7)/$B$8
=SUMIF(A2:A7,"Prune",B2:B7)/$B$8
=(SUMIF(A2:A7,"prune",B2:B7)+SUMIF(A2:A7,"durian",B2:B7))/$B$8
There's a standard formula you can use to calculate percent change in Google Sheets:
=(B-A)/A
The trick is to figure out which of your values belong to A and which to B.
Let's assume you had $50 yesterday. You have saved $20 more and today you have $70. This is 40% more (increase). If, on the contrary, you've spent $20 and have only $30 left, this is 40% less (decrease). This deciphers the formula above and makes it clear which values should be used as A or B:
Let's see how this works in Google Sheets now, shall we?
I have a list of fruits (column A) and I want to check how prices have shifted in this month (column C) compared to the previous one (columns B). Here's the percent change formula I use in Google Sheets:
=(C2-B2)/B2
I also used conditional formatting to highlight cells with percent increase with red and percent decrease with green:
This time, I'm tracking total sales (column B) over each month (column A). To calculate percentage change in rows, I use the following:
=(B3-B2)/B2
Copy the formula over all rows with data, apply the percent format, decide on the number of decimals, and voila:
Here I also colored percentage decrease with red.
If you take the same sales list and decide to calculate percentage change based on January only, you will have to always refer to the same cell - B2. For that, make the reference to this cell absolute instead of relative so it doesn't change after copying the formula to other cells:
=(B3-$B$2)/$B$2
Now that you've learned how to operate percentages, I hope getting total and amount will be a child's play.
Let's imagine you've spent $450 shopping abroad and you'd like to have the taxes returned - 20%. So how much exactly should you expect to receive back? How much is 20% of $450? Here's how you should count:
If you put the total to A2 and the percent to B2, the formula for you is:
=A2*B2
Another example: you've found a used scooter is being sold for $1,500. The price already includes a pleasant 40% off the original price. How much would you need to pay for a new scooter like that? The below formula will do the trick:
Since the discount is 40%, it means you are to pay 60% (100% - 40%). Then, calculate the original price (total) according to cells with data:
=A2/B2
=A2/0.4
=A2/40%
The following examples represent the formulas you may need a bit more often than other ones.
A general formula to calculate the raise by some percent is as follows:
Suppose you have some amount in A2 and you need to increase it by 10% in B2. Here's your formula:
=A2*(1+B2)
To decrease the number by a percentage, use the same formula as above but replace the plus sign with a minus:
=A2*(1-B2)
Now assume you have lots of records written in a column. You need to raise each of them by a percentage in that same column. There's a quick way (5 steps to be exact) to do that with our Power Tools add-on:
You will see %formula% is already written there. You are to add those calculations you want to apply to all formulas at once.
Remember the formula to increase a number by percent?
Well, you already have those amounts in column A - this is your %formula% for the tool. Now you should only add the missing part to calculate the increase: *(1+10%). The whole entry looks like this:
%formula%*(1+10%)
That's it! All these examples are easy-to-follow and are intended to remind those of you who've forgotten or show those who don't know the basic rules of calculating percentage in Google Sheets.