Guide
Wax melts: how much wax and fragrance oil per clamshell
A standard six-cavity clamshell holds roughly 2.5 to 3 oz of wax, so half a pound of wax fills about three clamshells. Many makers use 8% to 10% fragrance oil for melts, within the maximum listed for their wax. Weigh one of your own clamshells filled with water for an exact number.
Why wax melts are different from candles
A wax melt has no wick. It sits in a warmer that heats it gently from below, so the wax never burns. That changes a few things:
- Wax choice. Melts need a firmer wax that releases cleanly from the mold, often a pillar or melt-specific blend rather than a soft container wax.
- Fragrance. There's no wick to clog, so the usual limit is how much oil the wax can hold without sweating. Some melt waxes are made to take a higher load.
- Size. Each cube is small, so accurate weighing matters even more.
Step 1: Find how much wax your mold holds
Use the same water method as for candle jars. Weigh the water the clamshell holds when filled to your pour line, then multiply by the wax factor, about 0.86 for most waxes.
Pour weight per clamshell = water weight × 0.86
Clamshells vary by brand and cavity shape. Measure one from each new pack rather than trusting a listed size.
Step 2: Choose a fragrance load
CandleScience's clamshell recipe uses about 9%: 0.75 oz of fragrance oil for half a pound of wax, or 1.5 oz per pound. Many melt waxes are rated to 10% to 12%, and some higher. Start in the 8% to 10% range, then adjust after testing in a warmer.
Stronger isn't always better with melts. A small room fills quickly, and some fragrances can overpower at high loads. As with candles, check the IFRA certificate for each fragrance oil, which lists its maximum safe usage level.
Step 3: Work out the batch
Example: 10 clamshells holding 2.7 oz each, with fragrance at 10% of the wax weight.
- Total pour weight: 10 × 2.7 oz = 27 oz.
- Wax: 27 ÷ 1.10 = 24.5 oz (696 g).
- Fragrance oil: 24.5 × 0.10 = 2.45 oz (70 g).
Splitting the pour weight this way keeps each cavity filled to the same line once the oil is added. Add a few percent extra wax for what sticks to the pouring pitcher.
The wax melt calculator does this for you: enter the water weight of one clamshell, set the number of clamshells and your fragrance load, and it also works out the cost of each clamshell.
Pouring tips
- Heat the wax and add fragrance at the temperature your wax supplier recommends. CandleScience's recipe adds fragrance at 185°F (85°C) and pours at 170°F (77°C). Temperatures vary by wax.
- Stir gently for a couple of minutes so the oil binds with the wax.
- Pour on a level surface and let the melts cool completely, usually overnight, before closing the lids.
- Let melts cure before testing or selling. Like candles, fragrance often smells stronger after a few days to two weeks, depending on the wax.
Labeling
If you sell wax melts, include usage and safety directions, such as using a warmer designed for wax melts, never leaving a warmer unattended, and keeping it away from children and pets. Fragrance safety labeling rules depend on where you sell, so check the safety data sheet from your fragrance supplier.