Quick Answer — How Much Wax and Fragrance Oil Do I Need?
Wax weight is your container's fluid-ounce volume multiplied by the wax's specific gravity (its density relative to water): Wax Weight = Container Volume (fl oz) × Specific Gravity. A container's volume in fluid ounces is not the same as the weight of wax it holds — wax is lighter than water, so an 8 fl oz jar filled with soy wax (specific gravity 0.90) holds about 7.2 oz of wax by weight, not 8 oz.
Fragrance oil is calculated as a percentage of that wax weight, then added on top: Fragrance Oil Weight = Wax Weight × Fragrance Load %. Fragrance load is always measured by weight, not volume — fragrance oils are typically denser than wax, so a tablespoon or milliliter measurement gives inconsistent results batch to batch. Use a digital scale.
Every wax type has a manufacturer-set maximum fragrance load, the highest percentage the wax can fully absorb and bind. Soy, paraffin, and coconut wax typically top out around 10%, while beeswax — which already carries a natural honey scent and binds fragrance less readily — is usually limited to around 6%. Exceeding the maximum doesn't produce a stronger-smelling candle; it produces oil pooling on the surface (called sweating), a clogged wick, and inconsistent burning.