# Calculating fragrance oil percentage

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#### Teapot

I must first apologise, because I know this has been asked about a million times, and I've read numerous threads, but the more I read, the more confused I am.

I'm trying to calculate how much fragrance oil it's safe for me to use.

Soapcalc defaults to 0.5 oz ppo, which works out to just over 3% - I've used this, and had a nice smelling soap, not crazy strong, but strong enough for my liking. From the threads I've read, between 0.5 and 1oz ppo seems to be pretty standard.

On checking the manufacturer's recommendations, they say usage rate is 0.01% in a wash-off product. This seems like a very tiny amount. 0.01% is one-tenth of a percent, right? Am I missing something? Is my maths wrong?

I'm in the UK, looking in particular at FOs supplied by Just A Soap. Any comments or ideas anyone has would be really useful, because I just can't understand how FO at 0.01% can possibly be strong enough.

Well, I've answered my own question - sort of.

I've now found a separate document detailing IFRA usage limits, which for the FO I'm looking at, is 9.27%.

The allergen information states usage in finished product as 0.01% though.

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#### Kamahido

I generally start with 3% assuming the manufacturer doesn't say otherwise for soap.

#### TeresaT

##### I see you.
I was going to say that. I looked at the site. I thought perhaps you were using a FO that was high in spices. I purchased "Witches Brew" from a company and it does have a tiny IFRA max recommendation. If I had noticed that, I wouldn't have bought it. Glad you figured it out. Those IFRA sheets are my go-to guides.

#### IrishLass

Staff member
Moderator
Teapot said:
the more I read, the more confused I am.
Part of the confusion stems from the fact that not all fragrance oils have the same safe usage rate. They will often differ from each other depending on what they each contain.

I personally try to avoid buying fragrance oils that have low safe usage rates, and/or those that turn out weak in my soap when used safely. No sense wasting my money on such as those.

The best way I know of to pick winning fragrances that last in my soaps when used at their safe usage rates is to peruse IFRA or the fragrance manufacturer's guidelines, plus the handful of scent review boards that exist on the web, or ask about them on the forum.

For what it's worth- here my own personal FO protocol: I try to only use FOs that will 'stick' in my soap at usage rate not exceeding 1 oz ppo (6.25% ppo) at the very highest, providing that that falls within the safe usage rate. I stop at using anything more than 6.25%/1 oz ppo because that's a lot of FO, and they are not cheap. Plus, I don't want them to leach out of my soap or cause other problems. Most times, I find I can get by quite well with just .75 oz ppo (4.7%), and sometimes even less than that, depending on the particular FO.

IrishLass

#### Soapmaker145

##### Well-Known Member
Well, I've answered my own question - sort of.

I've now found a separate document detailing IFRA usage limits, which for the FO I'm looking at, is 9.27%.

The allergen information states usage in finished product as 0.01% though.
Fragrance oils have different IFRA limits for different types of products. You need to find the IFRA limits for soap/wash off products and calculate usage rates based on those numbers. I like FOs that I can use successfully at no more than 50% of the maximum usage rate for extra safety.

#### Soaparonie

##### Active Member
Part of the confusion stems from the fact that not all fragrance oils have the same safe usage rate. They will often differ from each other depending on what they each contain.
I found this in a google search. Im from the UK. Im terrible at calculations and am finding it difficult trying to work out how much fragrance oil/essential oil to use too. I get that these oils have different usage rates, but im wanting to know how much im able to use in a full 1kg loaf mould of soap, as a maximum amount.

Ive read some conflicting stories on websites. Some sites say its 3% in your finished soap and some say its 2%, and ive read that 2% is 20ml which seems quite a lot. Another site says to use 7g per pound, and there's two pounds in a kg, so that's 14g of fragrance oil/essential oil.

So far, ive got... 1g is equivalent to 1ml, and 1% is equivalent to 10g/10ml, is that right?

Im basically wanting to know how much i can use altogether in percentage, grams, ml, and drops. Any help would be appreciated, because im completely lost!

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#### KiwiMoose

Supporting Member
I'm pretty sure from reading other posts from UK peeps, that 3% of your oils weight is the maximum allowable if you want to register as a seller of soap.
@Soaparonie - it works out as a percentage of your oils weight. So if you have 1000g oils, you can use 30g FO. However, EO is not the same as FO, because some EOs are sensitising and guidelines vary depending on the oil - clove, cinnamon etc have a very low usage rate.
Also grams do not equal ml because most oils are quite light in weight - meaning that 30g of FO might actually be 40ml. You should never use 'drops' because it's not accurate enough.
@Teapot the trick will be to find FOs that have good scent strength/retention at 3% because if you ever want to register as a seller you will not be permitted to use more than that. Most citrus are known to 'not stick' as a rule. You will get to know which ones are strong enough at 3% by trialling some yourself and reading the reviews before buying will help point you in the right direction.

Sorry - just noticed this is a very old thread so it may fall on deaf ears.

#### Soaparonie

##### Active Member
Sorry - just noticed this is a very old thread so it may fall on deaf ears.
Thanks, i'll repost it.

it works out as a percentage of your oils weight. So if you have 1000g oils, you can use 30g FO. However, EO is not the same as FO, because some EOs are sensitising and guidelines vary depending on the oil - clove, cinnamon etc have a very low usage rate.
Also grams do not equal ml because most oils are quite light in weight - meaning that 30g of FO might actually be 40ml. You should never use 'drops' because it's not accurate enough.
Thanks. This was the youtube video where it said ml equals grams in the metric system. Skip to 3:10...

#### Raeyin

##### Member
This originally confused me because the numbers are different if you're making cold/hot process soap. Many numbers will reference the finished product. The saponification process turns much of the fragrance oil into soap. I'm making it for personal use, but when I started I was thinking, "I thought I used a low percentage! Why is it so intense?" It's because the chemical change eliminated most of it within days. I can't offer resources, but hopefully knowing that there is a difference will help.