How much wax and fragrance for a candle?
Size the wax to the vessel, the fragrance to the wax — and respect two limits.
Two numbers decide most of a container candle: how much wax fills the vessel, and how much fragrance oil goes into that wax. Get the first wrong and you over- or under-pour; get the second wrong and the candle can throw no scent — or worse, bleed oil and burn unsafely.
Wax: start from vessel volume
Wax is sold and measured by weight, but vessels are sized by volume, so you convert through the wax's density (specific gravity). Most natural waxes are a bit less dense than water:
Wax weight = vessel volume × wax specific gravity
A reliable shortcut is to fill the empty vessel with water to your fill line, weigh that water (1 mL water ≈ 1 g), then multiply by the wax's specific gravity. Soy container wax runs roughly 0.86–0.90; paraffin is a touch higher. For a vessel that holds 300 g of water and a soy wax at 0.90, you need about 270 g of wax. Multiply by the number of containers for a batch.
Fragrance load: a percentage of the wax
Fragrance load is the weight of fragrance oil expressed as a percentage of the wax weight (not the total):
Fragrance oil weight = wax weight × load %
Most container candles land at a 6–10% load. At 8% on 270 g of wax, that's about 21.6 g of fragrance oil. More oil is not automatically more scent — beyond the wax's capacity it simply doesn't bind, and the excess causes problems rather than throw.
1) Your wax's maximum load (the manufacturer's pour guideline — often around 10%, sometimes up to ~12% for container soy). 2) The fragrance oil's IFRA maximum for candles, listed on its IFRA certificate. Exceeding either invites oil seepage ("sweating"), poor adhesion, a clogged or drowning wick, sooting, and a real fire-safety risk. When the two disagree, the lower number wins.
Where the limits come from
- Wax max load — set by how much oil the wax can hold and still burn cleanly; it's in the wax's technical/pour sheet.
- IFRA limits — the International Fragrance Association publishes maximum usage levels by product category (candles fall under the non-skin-contact category). Each fragrance oil's IFRA certificate gives its candle maximum, which varies by the oil's components.
A worked example
| Step | Value |
|---|---|
| Water to fill line | 300 g |
| Wax specific gravity (soy) | 0.90 |
| Wax needed (300 × 0.90) | 270 g |
| Fragrance load | 8% |
| Fragrance oil (270 × 0.08) | 21.6 g |
Add fragrance to melted wax at the temperature your wax recommends (commonly around 185°F / 85°C for soy) and stir thoroughly so it binds before pouring.
Gear this guide uses
Weigh the wax and fragrance, hold the right pour temperature, and bind them in a pitcher.
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- Weigh wax and fragrance oil to the gram on a 0.1 g digital scale — fragrance load is a percentage of wax weight, so the scale sets it.
- Melt soy container wax in a pouring pitcher and add fragrance at the temperature on a thermometer.
Sources
Always follow the specific maximums on your wax's technical sheet and your fragrance oil's IFRA certificate; the figures here are typical ranges, not substitutes.