Fragrance Load for Wax Melts, Made Simple

You’ve poured a batch that looks perfect, pops cleanly from the mould, and then… the scent is faint. Or worse - it sweats oil, feels soft, and the clamshells come back from a market smelling like a spill. Nine times out of ten, the problem isn’t your moulds or your dye. It’s fragrance load - either miscalculated, mismatched to the wax, or pushed beyond what the blend can actually hold.

This is the good news: once you know how to calculate fragrance load for wax melts, you can make repeatable, scalable batches that smell strong and behave properly in storage, shipping, and warmers. The maths is easy. The judgement comes from knowing what the number really means.

What fragrance load actually means (and what it doesn’t)

Fragrance load is the percentage of fragrance oil in your wax melt formula by weight. If your recipe is 90% wax and 10% fragrance oil, your fragrance load is 10%.

It’s not a guarantee of strength on its own. Scent throw depends on wax type, oil composition, cure time, melt pool temperature in the burner, and even how much airflow you have in the room. But fragrance load is the lever you control first because it sets the ceiling for performance.

There’s also a practical distinction that matters when you’re making to sell: “maximum load” is what the wax can physically tolerate on paper, while “working load” is what stays stable and professional in real life (no sweating, no seepage, no soft brittle weirdness, no frosting you weren’t expecting). They’re often not the same number.

The only formula you need

You can calculate fragrance load in two directions, depending on how you prefer to batch.

If you know your wax weight and want to add fragrance

Use:

Fragrance oil (g) = Wax weight (g) x Fragrance load (%)

Example: 500g of wax at 10% load

500 x 0.10 = 50g fragrance oil

Total batch weight will be 550g (500g wax + 50g fragrance).

If you know your total batch size and want fragrance to be a true percentage of the whole

Use:

Fragrance oil (g) = Total batch (g) x Load (%)
Wax (g) = Total batch (g) - Fragrance oil (g)

Example: 500g total batch at 10% load

Fragrance = 500 x 0.10 = 50g
Wax = 450g

This method is useful if you’re filling a set number of clamshells and want your total output to land on a target weight.

Quick check to avoid the most common mistake

Makers often say “10% load” but calculate it as “10% of wax” or “10% of total” interchangeably. Either is fine if you’re consistent, but it changes the outcome.

If you do 10% of wax (500g wax + 50g oil) your fragrance is 50/550 = 9.09% of the total blend.

If you do 10% of total (450g wax + 50g oil) your fragrance is exactly 10% of the total blend.

In practice, the difference is small, but when you’re scaling to multiple kilos and trying to keep batches identical week after week, it’s worth choosing one method and sticking to it.

Worked examples for real wax melt batches

Let’s make this feel like your production table, not a maths lesson.

Example 1: You’re using 1kg of wax and want 8% load

Fragrance = 1000g x 0.08 = 80g

Total blend = 1080g

That’s a solid everyday load for many waxes and many fragrance styles, especially if you’re building a range with consistent performance across different scents.

Example 2: You want a 2kg total batch at 12% load

Fragrance = 2000g x 0.12 = 240g Wax = 1760g

This is where the “it depends” kicks in. 12% might be perfect for one wax and one oil, and messy for another. The calculation is correct either way - the formulation choice is what you test.

Example 3: Your clamshell holds 75g and you’re making 20 units at 10% load

Total required = 75g x 20 = 1500g

Fragrance = 1500 x 0.10 = 150g
Wax = 1350g

Add a small overage (say 2-3%) if you routinely lose a bit to the jug, stirring tool, or drips. That’s not waste - that’s planning for consistent filled weights.

Choosing the right fragrance load (without gambling your stock)

Most makers push fragrance load because they want stronger scent throw. Fair. But more fragrance doesn’t always translate to “stronger” once you get past the wax’s comfort zone.

At higher loads, you’re asking the wax to bind more oil. If it can’t, the excess oil can migrate. That shows up as sweating on the surface, oily patches inside the clamshell, or melts that stay too soft. You can also get poor snap or crumbling depending on wax and additives.

The sweet spot is usually the highest load that remains stable after curing and during normal storage conditions. For many makers that lands around 8-12%, but the honest answer is: your wax and your fragrance decide.

A few real-world trade-offs:

If you sell online and post year-round, stability matters as much as strength. A slightly lower load that never sweats in a warm delivery van can outperform a “max load” melt that arrives messy.

If you’re building a seasonal range, some fragrance styles naturally throw harder (think bakery, strong laundry types) while others are delicate. You may need to adjust load by collection rather than forcing every scent to the same percentage.

If you’re aiming for premium presentation, excessive fragrance can increase frosting, mottling, or surface imperfections depending on wax blend and pour temperature. Sometimes a tiny drop in load gives a much more retail-ready finish.

Weighing correctly: grams, not drops

If you want consistent batches, weigh everything in grams on a digital scale that can handle at least 2 decimal places for small tests. Volume measures (ml, teaspoons, “glugs”) will drift because fragrance oils have different densities.

Keep your workflow simple: tare your jug, weigh wax, melt, then tare again and add fragrance by weight. When your notes say 50g, you can repeat it exactly next week.

What to do if your melts sweat or smell weak

Sweating isn’t always “too much fragrance”. It can be too much for that specific wax at that specific temperature, or poor binding because of pour temps or mixing.

If your melts sweat:

First, confirm the calculation. Check you didn’t accidentally add 10% fragrance plus extra “to make it stronger”. Those little top-ups are where batches go off the rails.

Next, reduce load by 1-2% and retest. It’s a faster win than reformulating your whole process.

Then look at mixing time and temperature. Many makers under-mix because they’re trying to avoid air bubbles. A steady, thorough stir helps the wax and oil marry properly.

If your melts smell weak:

Give them time. Cure matters for wax melts too. Some fragrances bloom after a few days.

Check your burner setup. A burner that runs too hot can make a fragrance smell flat or “burnt out” quickly. A gentler warmer can actually smell stronger over time.

Consider that not every fragrance is designed to punch at the same level. If a scent is naturally lighter, raising load might help a bit, but choosing a stronger-performing fragrance profile often gives a bigger jump.

Batch notes that save you money

When you’re testing loads, change one variable at a time. If you change wax, load, pour temp and fragrance all in the same test, you won’t know what fixed it.

Write down: wax type, fragrance name, load %, weights used, pour temperature, room temperature, cure time, and how it performed after 24 hours, 72 hours, and a week. Those notes become your production playbook when you’re scaling and trying to keep customers coming back for “that exact scent”.

And if you’re selling, remember you’re not just chasing performance. You’re building consistency. Customers forgive a lot, but they don’t forgive a bestseller that smells different every restock.

A quick word on selling and compliance

Fragrance load is a formulation decision, but it affects your paperwork too. In the UK, your labels and safety information depend on the ingredients and their concentrations. If you change your fragrance load, you may change the classification.

That’s why keeping stable recipes matters. It’s also why having support for ready-to-use CLP labelling can remove a big headache when you’re growing a wax melt range fast. If you’re stocking up on oils and consumables anyway, Craftiful is built around strong-performing fragrances, same working day dispatch before 11am, and free CLP labels so you can focus on making and selling - not redoing admin every time you pour.

If you take one thing to the next batch, make it this: choose a load you can repeat, calculate it the same way every time, and test for stability as well as strength. The melts that sell out aren’t always the ones with the highest fragrance percentage - they’re the ones that perform perfectly in your customer’s home, every single time.