How candle wax calculator Works
Volume to weight — the step everyone gets wrong
Jars are labeled in fluid ounces (volume); wax is bought and weighed in ounces (weight). They are not the same: soy wax weighs about 0.86 oz per fl oz of container volume, paraffin blends closer to 0.90. The calculator converts your jar volume to wax weight, then adds fragrance as a percentage of the wax weight — the standard convention in candle making.
Fragrance load is a ceiling, not a goal
Every wax has a maximum fragrance load printed by its manufacturer — commonly 6–10% for soy blends. Exceed it and the oil doesn't bind: it sweats out, pools, and becomes a flare risk. "Stronger candle" beyond the max is actually a wick-size and cure-time problem. Check your wax's datasheet before choosing 10%.
The 10% headroom rule
Fill jars to ~80–90% of brim capacity (wick neck needs clearance, and wax expands hot). Our calculator assumes ~90% fill of the stated jar size — most "8 oz jars" hold their 8 oz to the brim. If your jar's spec sheet lists a "fill to" line, use that volume instead of the marketing size.