Candle Wax CalculatorHow Much Soy Wax Do I Need for My Candles?
Guessing wax amounts is the fastest way to waste money on a candle batch — you either melt far too much or run short halfway through pouring.
This calculator works out how much soy wax and fragrance oil you need. Measure your container's diameter and fill height, say how many candles you are making, and it does the volume, density, and fragrance-load math for you.
Soy wax calculator
Enter your container's diameter and height, how many candles you are making, and your fragrance load to get the wax and fragrance oil amounts — in grams, per candle and for the whole batch.
How the soy wax formula works
The calculator treats your container as a cylinder. Volume in cubic inches is π × (diameter ÷ 2)² × height. That is multiplied by 16.387064 to get milliliters, then by 0.86 g/ml — the density of soy wax — to get the wax weight for one candle.
That per-candle wax weight is multiplied by the number of candles, then increased by the margin percentage: wax_total = per-candle wax × candles × (1 + margin ÷ 100). The margin covers shrinkage as soy cools and losses to the melting pot and utensils.
Fragrance oil is calculated on the wax weight before the margin: fragrance_total = un-margined wax × (load ÷ 100). At an 8% load, that is the wax weight × 0.08 — 8 g of oil per 100 g of wax, the standard way fragrance loads are quoted.
Limits: containers are assumed to be straight cylinders — tapered or irregular vessels will read slightly high. The 0.86 g/ml figure is a typical density used to convert the volume of the finished candle (to the fill line) into wax weight; always weigh wax on a scale rather than scooping by volume.
Limitations of the calculation
The cylinder formula assumes straight-sided containers. Tapered vessels, jars with thick glass bases, or anything with curves will hold slightly less than calculated — the water displacement method is more accurate for those shapes.
Fragrance load is bounded by your specific wax: most soy waxes top out at 10%, and some fragrance oils have their own lower maximums. The calculator will happily compute a 10% load, but it cannot tell you whether your wax and oil combination will actually hold it — check your wax supplier's data sheet.
Finally, these are pre-pour amounts. Cure time, wick choice, and pour temperature all affect the finished candle, and none of them change the weights — but they do change how the candle performs, so the numbers here are the starting point, not the whole recipe.
Worked example: four container candles
Say you are pouring four candles into vessels 3 inches wide with a 3.5-inch fill height, at an 8% fragrance load with a 10% margin.
Step 1 — container volume: r = 1.5 in, so V = π × 1.5² × 3.5 = 24.74 in³. × 16.387064 = 405.42 ml per candle.
Step 2 — wax per candle: 405.42 ml × 0.86 g/ml = 348.7 g of soy wax.
Step 3 — batch wax: 348.7 g × 4 candles = 1394.6 g, plus 10% margin → 1534.1 g of soy wax to melt.
Step 4 — fragrance oil: 8% of 1394.6 g (the wax before the margin) = 111.6 g of fragrance oil.
So weigh out 1534.1 g of soy wax and 111.6 g of fragrance oil. The calculator above does all four steps instantly for any vessel size.
Related calculators
- Fragrance Oil to Wax Ratio CalculatorFree fragrance oil to wax ratio calculator: enter your wax weight and load % to get the fragrance oil in grams, with the formula explained.
- Water to Wax CalculatorFree water to wax calculator: weigh the water your container holds and convert it to wax weight for soy, paraffin, beeswax, coconut, or gel wax.
- Candle Wax Cost CalculatorCalculate candle batch costs with this free wax cost calculator.
Back to the free candle wax calculator: the homepage tool plus ten calculators.
Frequently asked questions
How much soy wax do I need for one candle?
For one container candle, measure the inside diameter and the fill height. The calculator treats the vessel as a cylinder: volume = π × (diameter ÷ 2)² × height, converted to milliliters, then multiplied by the soy density (0.86 g/ml). Multiply by your candle count and add a 10% waste margin — the worked example above walks through it step by step.
How much wax is in an 8 oz soy candle?
It depends on the vessel, not the label. A candle sold as '8 oz' usually refers to the vessel's liquid capacity in fluid ounces — a volume, not a wax weight. Enter that volume in the calculator to get the wax weight in grams; expect the gram figure to come out lower than the fluid-ounce figure, because soy wax is less dense than water.
What does an 8% fragrance load actually mean?
Fragrance load is fragrance oil as a percentage of the wax weight. An 8% load means 8 g of oil per 100 g of wax — on 500 g of wax, 40 g of oil, for a 540 g finished batch. Some makers quote a percentage of the finished candle instead; that is a different convention. This site always uses the percentage of wax weight, which is how most suppliers state fragrance load.
Can I use more than 10% fragrance oil in soy wax?
Most soy waxes accept 6–10% fragrance oil, with 8% the standard starting point. Going above your wax's rated maximum can cause sweating (oil beading on the surface), poor adhesion, or a weak burn. If you want a stronger scent, fix your wick and cure time first — extra oil rarely solves a weak throw.
Can I skip the waste margin?
No — that is what the waste margin is for. Soy wax shrinks as it cools, and some wax always stays behind in the melting pot and on utensils. A 10% margin covers both. Without it, makers typically run short by half a candle per batch and end up melting a second, tiny batch.
Should I measure melted wax by volume or weight?
Weigh it. The 0.86 g/ml figure is a typical density used to convert the volume of the finished candle (to the fill line) into wax weight. Do not melt it and measure it in a jug: molten wax is less dense, so a milliliter of liquid wax weighs less than the figure the calculator uses, and you would under-fill.
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