February 17, 2022 3 min read

Working With Percentages

If you’re a regular reader of our blogs, you may have noticed that for the last while we’ve switched from using measurements in recipes to using percentages. The reason for this is that percentages are a universal unit, and you can convert them into whatever unit of measure you feel most comfortable with. They’re also way more accurate.

 

We’ve had a couple of people ask how to work with percentages so we thought we’d create a blog article dedicated to just this! Don’t be scared of percentages - they’re actually rather lovely to work with, and are an elegant solution to converting to different types of measurements.

 

So, what exactly is a percentage?

‘Percent’ means ‘of one hundred’ or one part of a 100.

To help you understand more, here are some percentages in fractions, decimals formats and parts:

50% is 50/100, which is half, which can also be written ½, etc. It would be 1 part X to 1 part Y.

33.33% is 33.33/100, which is a third, ⅓, etc. It would be 1 part X to 2 parts Y.

10% is 10/100, which is a tenth, 1/10, etc. It would be 1 part X to 9 parts Y.

A formula in percentages must always add up to 100%, because 100% is 100/100 which is the full amount.

 

Converting To Grams

I like to think of 100% = 100g because keeping the 100s the same is easy and I like working in grams because I have a little scale that measures in grams. It's a 1-for-1 conversion.

In the same way, 50% = 50g, 0.5% = 0.5g and so on.

 

Here is an example in formula format:

 

Heated water phase

70% | 70 water

2% | 2  vegetable glycerine

Heated oil phase

15% | 15  oil of choice

5% | 5  solid oil/butter of choice

2% | 2  cetyl alcohol

5% | 5  Eco E wax

Cool down phase

1% | 1  Geogard 221

 

Do you see how removing the % makes the numbers on the right look more friendly? Now you can basically replace that % with a unit of measurement such as grams, and voila! You have your measured amount. This will always yield a 100g batch of course, but that’s quite a nice batch size anyway so most of the time I don’t even bother scaling to a different amount - but we’ll learn how to do that further down this page.

 

Converting To Mililitres

If you prefer to work in mils instead of grams you can think of 100% = 100ml and work it from there.

50% = 50ml, 34% = 34ml and so on.

Convert the % directly into mils.

 

NB: There is one rule, and that is keeping your chosen unit of measurement uniform throughout the formula. So do not mix up different units of measurement in a formula. Don’t use grams and mils together, keep to one or the other. 

 

Scaling With Percentages

Percentages are ideal to scale a recipe with. The percentage amount will never change; only your units of measure will because percentages are universal: 50% is 50% no matter what batch size or measurement you use.

 

Say we want a 500g batch size instead of the usual 100g. You will simply need to multiply all your gram measurements by 5, because 5 x 100g = 500g (or you can look at it this way: 500/100 = 5. Whichever way works best for you). 5 is your scaling amount.

 

In the same way:

50% = 50g, and this measured amount gets multiplied by 5 to make 250g. And hey, 250g is half or 50% of 500g, so it all checks out. Simply multiply your measured amounts by your scaling amount (in this case, 5).

 

Another example:

26% = 26g multiplied by 5 equals 130g. And 130/500 equals 26%.

 

If you wanted to scale your batch down, you would do a similar process.

Say you wanted a 30g batch instead of 100g. Your scaling amount is 0.3 because 100 x 0.3 = 30 (or you can look at it this way: 30/100 = 0.3. Whichever way works for you).

 

To scale your percentages:

50% = 50g multiplied by 0.3 equals 15g. To check, 15/30 = 50%.

 

As you have hopefully seen, working with percentages is really just a matter of converting directly to your measured amounts, and it's a universal ‘unit’ which is pretty neat. We will always be working in percentages for formulas going forward.


2 Responses

Clara
Clara

February 22, 2022

Thanks a lot for the wonderful explanation on percentage

Terry Norton
Terry Norton

February 21, 2022

YAY !!! thanks so much for making this accessible to your " JO SOAPS " out here , so appreciated

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