How To Work Out Percentages - Making Maths Easy

Our Percentage Calculator makes it easy to calculate the percentage of any
number. Just enter the percentage you want to find in the first box, then the number you want to find the percentage of in the second box and click Enter. You can also find what one number is as a percentage of another by picking this option from the drag down menu and clicking Enter. Calculating percentages has never been easier! See our other Percentage Calculators.

How to Work Out Percentages on a Calculator

This Simple site has one aim - to show you how to work out percentages, easily. This is an invaluable skill - and is critical if you work in a business of any type or simply if you want to know if you are getting a good deal on that new TV or Car.

Percentages Are Simple - so before we get started - don't panic! If you follow the site you will see percentages are not as difficult as you thought and you will be calculating percentages before you know.

Guide to How To Work Out Percentages

How To
Work Out Percentages, How To Work Out Percentages

Lesson 1 - What is a Percentage?

Simply put, a percentage is a share of something. Think of a cake. If I ask for a piece of your cake how much should you cut for me. Half? A quarter? These are just different ways of expressing a percentage.

When working out percentages we assume our cake (or pie, or pile of cash or whatever) is divided into 100 shares or parts. Each 100th part is 1 percent of the cake, so if I have all 100 parts I have 100 percent of the cake (or 1 whole cake!)

If you have 50 parts, you have 50 percent of the cake etc.

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Lesson 2 - How to write a Percentage?

You just add the % symbol after the number, for example 50%. You can write 50 percent if you wish though.

(Note you can normally find the % symbol on your keyboard by pressing shift+5 together).

Lesson 3 - How To Work Out Percentages

Simple - the easiest way to see is to follow this example. Say I have a new cake and my friend Bill asks me for some. I want to make sure I get the % correct so Bill will have to wait a while. The first thing I do is cut my cake into 100 small pieces, 1 for each percent (%) of the cake. I decide to give Bill 25 pieces, so 25% of my cake. But, how much do I have left?

Simple - I count the pieces of cake I have left which is 75 (Originally I had 100 pieces and I gave 25 pieces to Bill). I now divide the number of pieces I have left, so 75 by the number of pieces I had originally, so 100 (75/100) and what do I get - 0.75. What is this you might ask? I though we were working out percentages!

Don't panic, we are. To recap -

When we have a cake cut into 100 pieces, we have 100 pieces or 1 whole cake. If we give 25 pieces (25%) to Bill we no longer have 1 whole cake, rather we have the remaining 75 pieces (75%) or to put it another way 0.75 of a whole cake of 100 pieces.

You see - easy peasy!

The great thing about working out percentages is that you do not even need to cut your cake into 100 pieces and it will still work the same. Say I have another new cake and I cut it into 30 pieces. As I have 30 pieces I have 100% of the cake, or 1 whole cake. If I decide to give Bill 10 pieces how much do I have left to eat? Following the same method I count the pieces of cake I have left which are 20 (Originally 30 pieces and I gave 10 pieces to Bill). I now divide the number of pieces I have left, so 20 by the number of pieces I had originally, so 30 (20/30) and what do I get - 0.66 or 66%.

(Note: For doing the dividing one number by another I use a calculator so no need to waste time on manual sums)

Lesson 4 - How to Work Out Percentage Increase?

Now we are really moving!! You will be glad to hear that the process is the same as in Lesson 3 - How To Work Out Percentages.

Now I have made myself yet another cake (I am getting a bit fat now). I have cut it into 100 pieces again ready for when Bill comes round, but this time when Bill comes round he has brought his own cake (I almost fainted). Bill has also cut his cake into 100 pieces and he kindly gives me 40 pieces of his cake. Now, I know I have more cake than before but how much more? This is where percentage increases come in useful.

Firstly following the same method as above I count the pieces of cake I have now: 100 from mine + 40 from Bill's cake so 140 pieces in total. I now divide the number of pieces I have now, so 140 by the number of pieces I had originally, so 100 (140/100) and what do I get - 1.4 or 140%. To work out percentage increase there is one more step. We must now subtract the number of pieces we originally had, so 100 pieces or in other words 100%. So we calculate percentage increase by 140% - 100% leaves 40%.

This means when Bill gave us 40 pieces of cake we ended up with a 40% more cake than before, or to put it another way a percentage increase of 40%.

Lesson 5 - How to Work Out Percentage Decrease?

Easy peasy!

Believe it or not I have made myself yet another cake (getting bored of cake now). I have cut it into 100 pieces again ready for when Bill comes round and this time Bill asks me for 60 pieces of cake. Now, I know I have less cake than when I started but how much less? This is where percentage decreases come in useful.

Firstly I count the pieces of cake I have now: 40 pieces (as we gave Bill 60 pieces from our original 100 pieces). Next we must subtract the number of pieces we have now (40 pieces) or from the number of pieces we originally had (100 pieces), so 100-40 = 60 pieces. As each piece of cake is equivalent to 1% of the cake (as we cut our whole cake into 100 pieces at the start) we calculate percentage decrease by 100% - 40%, leaves 60%.

This means when we gave Bill 60 pieces of cake we ended up with a 60% less cake than before, or to put it another way a percentage decrease of 60%.

Lesson 6 - How Percentages Can Help You Make Decisions

Percentages are everywhere! One of the best examples is when shopping. You see a TV you like in a store and it shows a saving of £150 and the original price was £400. Next to it is a TV with a message saying save 30%. Which is the better offer?

Using what we have learnt above we could calculate percentage saving on the first TV for comparison. So saving £ divided by the original price £ = saving %, so £150/£400 = 0.375 or 37.5% so definitely a better deal than the second TV.

Percentages are useful in many areas: how much faster can I run the 100m than last week? How much has my weight dropped in the last week? All key questions that percentages can help you work out and allow you to easily track your process.

If you want to own your own business, how do you measure how it is performing? One again you need to be able to calculate percentages to track performance and take action accordingly.

So now you know How To Work Out Percentages. Good luck in all your percentage calculations!

Extra Lesson - Percentage Formula, Percentages Worksheets

To work out percentages very quickly use this formula: Figure you want to see as a % divided by Figure you are comparing it with (base figure) x 100.

To work out percentage increase very quickly use this formula: Figure you want to see as % divided by Figure you are comparing it with (base figure) minus 1 then x 100.

To work out percentage decrease very quickly use this formula: Figure you want to see as % divided by Figure you are comparing it with (base figure) minus 1 then x 100.

If you are using Excel you can write percentage calculator formula very easily:

Percentage formula: =Figure you want to see as a % / by Figure you are comparing it with (base figure) * 100. E.g. =50/200*100, so 25%

Percentage change formula. It is easiest to enter the formula split between two different cells on the spreadsheet (percentage worksheet):

Cell 1 formula: =New figure for comparison - (minus) Base figure E.g. =120-80

Cell 2 formula: =(Cell 1 / by Base figure you are comparing it with) * 100. E.g. =(cell 1/80)*100, so 50%. (Note remember the brackets in your formula!).

You are now an expert in How To Work Out Percentages!

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