Multi-Container Candle Fill Calculator

Why you cannot just fill containers with liquid wax:

Wax shrinks as it cools, typically 5 to 10% by volume depending on the type. Pour the exact container volume in liquid wax and you get sinkholes and a dished top. Plan for the shrinkage and for a second, smaller relief pour.

Wax density and volume conversion:

Different waxes have different densities when solid. The g/cm³ column below is the same set of figures our wax weight and taper pages use, so all three give the same answer for the same jar:

The third column is the second multiplied by 1.0432, since a US fluid ounce of water weighs 1.0432 weight ounces rather than exactly one.

Container volume formula:

For a cylindrical container: Volume (fl oz) = π × (diameter/2)² × height × 0.554 (all measurements in inches)

That 0.554 is just the conversion from cubic inches: one cubic inch is 0.554 fluid ounces.

Wax weight formula:

Wax weight (oz) = Container volume (fl oz) × fill fraction × weight-per-fl-oz factor

Fragrance load:

Fragrance oil (oz) = Total wax weight (oz) × fragrance percentage / 100

Standard fragrance loads:

• Soy, paraffin and coconut blend: 6–12%, with most makers at 6–8%
• Beeswax: 6–8%, it holds noticeably less than the others

Worked example:

Filling 12 jars, each 3" diameter × 3.5" tall, with soy wax at 8% fragrance:

• Volume per jar = π × 1.5² × 3.5 × 0.554 = 13.7 fl oz
• Fill to 90% (leave headroom): 13.7 × 0.90 = 12.3 fl oz
• Wax weight per jar: 12.3 × 0.908 = 11.2 oz
• Total wax: 11.2 × 12 = 134.4 oz (8.40 lbs)
• Fragrance oil: 134.4 × 0.08 = 10.8 oz
• Add 10% extra for waste and spills: wax = 9.24 lbs, fragrance = 11.8 oz

Always melt 10 to 15% more wax than calculated. Wax sticks to the melting pot, the pouring pitcher and the thermometer, and you will want extra on hand for the relief pour that fills the sinkholes.