How to Calculate Fragrance Load for Candles

If you make candles in the UK, one of the most useful things to understand is fragrance load. It affects scent strength, burn quality, stability, cost, and even labelling. Get it right and you have a candle that smells good both cold and hot, burns cleanly, and performs consistently. Get it wrong and you may end up with sweating, poor wick performance, weak scent throw, or a candle that simply does not burn as it should.

This guide explains how to calculate fragrance load for candles in a clear, practical way, with a focus on UK candle making. We will look at what fragrance load means, how it relates to different types of candle making wax in the UK, the maths behind the calculation, and the common mistakes that trip people up.

What fragrance load means in candle making

Fragrance load is the amount of fragrance oil used in relation to the wax. It is usually expressed as a percentage. In simple terms, it tells you how much scent oil is added to your candle wax.

For example, if you use 100g of wax and add 8g of fragrance oil, your fragrance load is 8%. If you use 1kg of wax and add 100g of fragrance oil, your fragrance load is 10%.

This sounds straightforward, but there are two points that often cause confusion:

Some makers calculate fragrance load as a percentage of the wax weight only.
Others calculate it as a percentage of the total finished candle weight.

In the UK candle making industry, when a wax supplier says a wax has a maximum fragrance load of 10%, they usually mean 10% fragrance oil compared with the wax weight, not the total finished weight. That is the method used in most home and small business candle making recipes, and it is the method this article focuses on.

Why fragrance load matters

It is tempting to think that more fragrance oil will always mean a stronger-smelling candle. In practice, it is not that simple. Every candle making wax has a point beyond which it struggles to hold more oil properly. If you exceed that point, the extra oil may separate from the wax, affect the surface finish, clog the wick, or create an uneven burn.

Fragrance load matters because it influences:

Cold throw – how strong the candle smells before lighting
Hot throw – how strong the scent is when the candle is burning
Wax appearance – including sweating, frosting, sinkholes, or rough tops
Burn performance – wick size, flame height, mushrooming, and melt pool formation
Costing – fragrance oil is often one of the most expensive parts of the recipe
Safety and compliance – more oil can affect CLP information and product performance

That is why experienced candle makers test carefully rather than assuming the highest possible fragrance load is the best choice.

Fragrance load and candle making wax in the UK

UK candle makers commonly work with soy wax, rapeseed wax, coconut blends, paraffin, and mixed container waxes. Each wax type has its own characteristics and its own recommended fragrance range. The exact figure depends on the supplier and formulation, so always check the technical data sheet for the wax you are using.

Common wax types and typical fragrance ranges

Soy container wax – often around 6% to 10%
Rapeseed or rapeseed/coconut blends – often around 8% to 12%
Paraffin wax – varies widely, often around 6% to 12%
Pillar waxes – often lower or more tightly controlled than container waxes

These are only rough guides. A UK supplier may list a maximum fragrance load, but that does not mean every fragrance oil will perform well at that level. Some oils are heavier, some are more volatile, and some interact with wax more easily than others.

For example, a soy wax sold in the UK might say it can hold up to 10% fragrance. That does not automatically mean every candle made with that wax will be best at 10%. One fragrance may work beautifully at 8%, while another may need 10% for a decent hot throw, and a third may start to sweat if you go above 7%.

The basic formula for calculating fragrance load

The standard formula is:

Fragrance oil weight = Wax weight × Fragrance load percentage

You must convert the percentage into a decimal for the calculation.

6% = 0.06
8% = 0.08
10% = 0.10
12% = 0.12

Example 1: 500g of wax at 8% fragrance load

500 × 0.08 = 40

You need 40g of fragrance oil.

Your total mixture will be 540g.

Example 2: 1kg of wax at 10% fragrance load

1000 × 0.10 = 100

You need 100g of fragrance oil.

Your total mixture will be 1100g.

Example 3: 750g of wax at 6%

750 × 0.06 = 45

You need 45g of fragrance oil.

Your total mixture will be 795g.

How to work backwards from your container size

Many candle makers do not start with a wax weight. They start with jars. For instance, you might have twelve amber jars and know each one takes about 180g of finished wax and fragrance combined. In that case, you need to work backwards.

Let us say you want twelve candles at 180g finished weight each.

Total finished weight needed:

12 × 180g = 2160g

Now you need to split that total between wax and fragrance oil.

If your fragrance load is based on wax weight, use this formula:

Wax weight = Total finished weight ÷ (1 + Fragrance load decimal)

Example: 2160g finished weight at 8% fragrance load

Wax weight = 2160 ÷ 1.08 = 2000g

Fragrance oil = 2000 × 0.08 = 160g

So for twelve candles with a total finished weight of 2160g at 8% fragrance load, you need:

2000g wax
160g fragrance oil

This approach is especially useful when batching candles for a small business and trying to minimise waste.

A quick reference table

Here is a simple guide for common wax quantities:

For 1kg of wax

6% load = 60g fragrance oil
7% load = 70g fragrance oil
8% load = 80g fragrance oil
9% load = 90g fragrance oil
10% load = 100g fragrance oil
12% load = 120g fragrance oil

For 500g of wax

6% load = 30g fragrance oil
7% load = 35g fragrance oil
8% load = 40g fragrance oil
9% load = 45g fragrance oil
10% load = 50g fragrance oil
12% load = 60g fragrance oil

For 100g of wax

6% load = 6g fragrance oil
7% load = 7g fragrance oil
8% load = 8g fragrance oil
9% load = 9g fragrance oil
10% load = 10g fragrance oil
12% load = 12g fragrance oil

How to choose the right fragrance load

The best fragrance load is not always the maximum allowed by the wax. It is the level that gives you a stable, good-performing candle with the scent strength you want.

When choosing a starting point, consider the following:

1. Supplier recommendations

If your UK wax supplier recommends 6% to 10%, start within that range. If they give a maximum, treat it as a ceiling rather than a target.

2. Type of fragrance oil

Some oils are naturally strong and work well at lower levels. Others are lighter and need more support. Citrus oils, for instance, can be more delicate in candles than heavier gourmand or woody blends.

3. Container or pillar candle

Container waxes often handle fragrance differently from pillar waxes. A wax intended for jars may be more forgiving than one designed for moulded candles.

4. Wick performance

Adding more fragrance changes how the candle burns. If you raise the fragrance load, you may need to retest your wick size because the candle can burn hotter or struggle to maintain a proper melt pool.

5. Cost per candle

Fragrance oil can significantly increase your production costs. Moving from 6% to 10% may improve scent in some cases, but it can also reduce your profit margin if the improvement is slight.

A sensible testing approach is to start at 6% or 8%, depending on the wax, then compare with a slightly higher level such as 8% or 10%. That gives you a meaningful performance comparison without making testing overly complicated.

Common mistakes when calculating fragrance load

Confusing wax weight with total candle weight

This is one of the most common errors. If a recipe calls for an 8% fragrance load, it generally means 8% of the wax weight, not 8% of the total candle weight. If you mix up the two methods, your recipe will be off.

Using volume instead of weight

Always measure wax and fragrance oil by weight, not by millilitres or spoonfuls. Different oils have different densities, so volume measurements are not reliable enough for consistent candles.

Ignoring the wax maximum

If your wax is rated for up to 10% fragrance, pushing it to 12% without proper testing can create problems. Even if the wax seems to take the oil at first, performance may fall apart during burn tests.

Assuming more oil means better scent throw

Beyond a certain point, adding more fragrance can actually reduce performance. A heavily loaded candle may burn poorly, trap fragrance in the wax, or produce soot and mushrooming.

Not adjusting wick testing

Fragrance load, wax type, dye, jar size, and wick all affect one another. If you change fragrance percentage, retest the wick rather than assuming your old setup is still suitable.

The role of cure time

In UK candle making groups and supplier advice pages, cure time comes up again and again for good reason. The fragrance load may be correct, but if you judge the candle too soon, the scent throw may seem disappointing.

Different waxes benefit from different curing periods:

Soy wax often benefits from around 1 to 2 weeks, sometimes longer
Rapeseed and blended waxes vary depending on formulation
Paraffin wax often needs less curing time

If you test a candle one day after pouring and decide the fragrance load is too low, you might be making a judgement too early. Let the candle cure according to the wax supplier’s advice before deciding whether to increase or reduce the fragrance percentage.

UK practicalities: grams, compliance, and supplier data

In the UK, most candle makers work in grams and kilograms, which makes fragrance load calculations quite easy. A digital scale with 0.1g or 1g accuracy is one of the best tools you can buy, depending on batch size.

There are also a few UK-specific practical points worth keeping in mind:

CLP labelling

If you are selling candles in the UK, your fragrance oil affects the hazard classification and CLP label requirements. The exact amount of fragrance oil in the candle matters, so accurate calculation and record-keeping are important.

Supplier documentation

Good UK suppliers usually provide:

Wax technical data sheets
Recommended pour and melt temperatures
Maximum fragrance load guidance
Fragrance oil safety data sheets
Often an allergen or CLP document for the oil

These should form part of your testing process. Do not rely only on general internet advice when your specific wax and oil have their own limits.

A step-by-step method for calculating and testing fragrance load

Here is a straightforward process you can use for any candle making wax in the UK.

Step 1: Check the wax specification

Look up the recommended fragrance range and maximum load for your wax.

Step 2: Pick a test percentage

Choose a sensible starting point, such as 6%, 8%, or whatever suits the wax.

Step 3: Weigh the wax

Decide how much wax you need for the test batch.

Step 4: Calculate the fragrance oil weight

Use the formula:

Wax weight × fragrance percentage decimal

Step 5: Melt and add fragrance properly

Follow the wax supplier’s recommended temperature range for adding fragrance oil and mixing thoroughly.

Step 6: Pour and cure

Allow the candles to set and cure for the appropriate time.

Step 7: Burn test

Assess cold throw, hot throw, melt pool, flame behaviour, soot, and jar temperature.

Step 8: Compare with other percentages

If needed, repeat with a higher or lower fragrance load and compare results side by side.

Worked example for a small UK batch

Imagine you are making six container candles using a soy wax available from a UK supplier. Each jar holds about 220g of finished candle. You want to test an 8% fragrance load.

Total finished weight:

6 × 220g = 1320g

Now calculate wax weight:

1320 ÷ 1.08 = 1222.2g wax

Now calculate fragrance oil:

1222.2 × 0.08 = 97.8g fragrance oil

You would round sensibly based on your scale and process, for example:

1222g wax
98g fragrance oil

Total = 1320g

If you then wanted to compare this with a 10% version:

1320 ÷ 1.10 = 1200g wax

1200 × 0.10 = 120g fragrance oil

That gives you a clean side-by-side comparison for testing.

How fragrance load affects cost

For UK candle businesses, fragrance load is not just a technical issue. It is a pricing issue too.

Suppose your fragrance oil costs £18 per kilogram. At 6%, you use 60g per kilo of wax. At 10%, you use 100g per kilo of wax. That difference adds up across large batches.

If two candles smell equally good to your customers, but one uses 8% and the other uses 10%, the 8% version may be the better business choice. This is why testing is so important. It helps you find the point where performance and cost make sense together.

Final thoughts

Calculating fragrance load for candles is not difficult once you know the formula, but using that figure well takes testing and patience. For UK candle makers, the key points are simple: work in grams, calculate fragrance as a percentage of wax weight, stay within the wax supplier’s guidance, and test properly before deciding that a higher load is better.

Whether you use soy, rapeseed, coconut blends, paraffin, or another candle making wax sold in the UK, the same principle applies. A well-made candle is not the one with the most fragrance oil. It is the one where wax, wick, fragrance, container, and cure time all work together.

If you keep clear records of your wax weight, fragrance percentage, pour temperature, cure time, and burn test results, you will find it much easier to repeat successful batches and improve weaker ones. That makes fragrance load calculation more than just a bit of maths. It becomes one of the foundations of reliable candle making.