How to Calculate Fragrance Scent Load

You’re all ready to go, keen to make a new batch of candles. You’ve worked out you need 300g of candle wax to fill your base and you know your wax can take a scent load of 10%. So you take 10% from 300g which is 30g, therefore you need 30g of fragrance oil and 270g of wax. Easy peasy…

Hold up! Before we go any further, let’s talk about what you’ve done so far and what issues you may run into. Tunnelling, poor scent throw, and wicks not staying lit could be a real issue here because the calculation you just used isn’t quite right.

What exactly is scent load?

Let’s take a step back. There is some confusion in the industry about what exactly scent load is. We simply explain it as the ratio of fragrance oil to the weight of your wax. Yes, 30g is 10% of 300g, but it’s not 10% of the wax weight, which is what you need. A 10% scent load of 300g would actually be 30g of fragrance oil added to 300g of wax, making your finish product weight 330g. Adding 30g of oil to 270g of wax works out at approximately 11.11% fragrance oil - way more than the 10% scent load your wax can take! If you keep working it out this way, you’ll always overload your wax with fragrance oil.

It’s good to note what happens if your wax does become overloaded with fragrance oil. You could be experiencing other common issues without knowing it’s your oil to wax ratio causing the issue. Here’s what you should look out for:

• The wick tends to struggle and will only achieve a small flame, or sometimes the flame will die completely.
• A struggling wick could result in candle tunnelling or not achieve a full melt pool.
• The candle can also have poor hot throw as there’s not enough heat being generated to allow the fragrance to release from the wax.

If you experience any of these common issues, why not try lowering your fragrance oil percentage and see if this resolves them. We recommend that candle makers use 8% fragrance oil for their candles unless it’s a really light oil. This will help keep the wick from clogging and avoid poor performance problems, like those listed above.

Calculating The Right Weights

So how do you calculate the right scent load for your candle wax?

To keep things simple and give a helping hand, we’ve created a calculator that’ll do the maths for you. All you have to do is enter the amounts you already know: your desired candle weight and the percentage of fragrance oil you want.

Let’s try the calculator with our example from earlier. We had a desired candle weight of 300g and we want 10% fragrance oil.

You should see that you actually only need 272.7g of wax and 27.2g of fragrance oil. That’s over 2g less than before and could make all the difference in your candles.

It’s super simple to use and that’s exactly why we made it for you. Don’t forget: If you need to know how much wax weight and fragrance weight is needed for a batch of candles, you can also add you candle quantity to the calculator!

Another Important Factor To Know

Fragrance oil ratio can also affect the percentage used in CLP (classification, labelling and packaging). It’s an EU legal requirement that must be met as it pertains to hazardous goods. That’s why we asked our own CLP consultant to give her expert view of what this means:

“Prior to June 2015, candle makers only had to consider the Scent Load Ratio when making their products.  However, since the CLP regulations came into force on June 2015 some confusion has crept in which has led to candle makers talking  in general about ‘the percentage of fragrance oil’ in their products. It’s important to understand that Scent Load and the percentage given on Safety Data Sheets (SDSs) (and thus the percentage of fragrance oil percentage used to create the CLP templates)  are NOT calculated the same.

Scent Load, as discussed above is based on the ratio of fragrance oil to wax, but in terms of CLP the fragrance oil percentage is based on the amount of fragrance in the total weight of the product.   So, when 10% is given as the amount calculated for the SDS / CLP this means that 10% of the total weight of the product comes from the fragrance oil and the other 90% comes from ‘other substances’ like candle wax.

When a candle maker uses (for example) 30g to 300g of wax, this gives a Scent Load of 10%, but the total percentage of fragrance oil, for CLP purposes is actually 30g in 330g because 330g is the total weight of the product (i.e. 30g + 300g) which gives a CLP percentage of 9.09%.  

For most candle makers, who purchase fragrance oils from a supplier who also provides the CLP template, it’s  advisable to double check your Scent Load and the amount of fragrance you use for CLP purposes, to ensure you are fully compliant (i.e. have not accidentally used more fragrance oil in your products than the CLP template allows).    

If you create your own blends and / or have SDS / CLP information created (because you use an oil whereby the supplier has not provided the CLP template) then it’s vital that any percentages you provide your CLP consultant are based on the actual amount of fragrance oil in the total weight of the product and NOT the scent load ratio, as you could be in a position of having CLP information created that is not accurate for your needs.”

So not only is it important to get your Scent Load calculation right to ensure your candles can perform at their best, it’s also really important to get right for CLP, so you can sell them legally.

To get more information, guidance or support on Scent Load, we’re always happy to help via our online chat, email or telephone.