How much wax and fragrance for a candle?
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.
Wick does this math with the guardrails built in
Enter your vessel and wax and Wick returns the wax weight and the fragrance oil for your target load — and warns you when you cross the wax's max or the fragrance's IFRA limit. It also sizes the wick and totals your per-candle cost. Free to download.
Sources
- IFRA Standards (International Fragrance Association) — product-category usage limits
- Wax manufacturers' technical/pour guidelines for maximum fragrance load (e.g., soy container blends)
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.