Candle Making Calculator

Candle making ratios decide how much wax and fragrance oil go into a container, and how big a wick that container needs to burn cleanly.

Core formulas: Wax Weight (oz) = Container Volume (fl oz) × Wax Fill Factor Fragrance Oil (oz) = Wax Weight (oz) × Fragrance Load %

Note that fragrance is a percentage of the wax, not of the finished candle. Getting that backwards is a common slip and it under-doses the scent by roughly the fragrance percentage itself. Dye is not calculated here: liquid dye, dye chips and dye blocks are all measured differently and every supplier states its own rate on the packet.

Wax fill factor by wax type:

• Soy wax (container): 0.85, so 1 fl oz of container volume needs about 0.85 oz of soy wax
• Coconut wax: 0.85, near enough to soy that you can swap them by weight
• Paraffin (container): 0.90, slightly denser than soy
• Beeswax: 0.96, the densest of the four

The fill factor is ounces of wax per fluid ounce of container. It is not a density in the physics sense: it already accounts for the fact that you do not pour to the brim, and for the small amount of shrinkage as the wax sets. Suppliers publish it this way, which is why you can read a jar’s stated capacity straight off the label and multiply.

Fragrance load by wax type (maximum safe load):

Worked example: You’re making a 12 fl oz soy candle with a 9% fragrance load.

Wax weight = 12 × 0.85 = 10.2 oz of soy wax Fragrance oil = 10.2 × 0.09 = 0.918 oz, about 26 g or 27 mL of fragrance oil Total pour weight = 10.2 + 0.9 = 11.1 oz total

Temperature guidelines:

• Melt soy wax to 170–180°F
• Add fragrance oil at 140–160°F (prevents flash-off and ensures binding)
• Pour into container at 120–135°F (prevents sinkholes and cracking)

Wick sizing: wick size follows the container diameter, not its volume. A tall narrow jar and a short wide one can hold identical wax and still want completely different wicks, because what the wick has to do is carry a melt pool out to the glass. Too small and you get tunnelling, a hole burned down the middle with an inch of untouched wax around it. Too large and it soots, mushrooms, and runs hot enough to be a genuine hazard in a thin jar.

These are starting points for soy, not answers. Fragrance oil, dye and jar thickness all shift the burn, so test-burn three candles for a full 4 hours before committing to a wick for a production run. A candle that tunnels on the first burn will tunnel forever, because wax has a memory for the melt pool it made first.