How 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 exactly 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 exact wax and fragrance oil amounts — in grams, per candle and for the whole batch.

1 Step 1: Your container

Inside diameter of the container, measured across the top
How high you plan to fill the wax, not the height of the vessel

2 Step 2: Batch and fragrance

How many candles you are pouring in this batch
Fragrance oil as a percentage of the finished candle weight
Extra wax added for shrinkage, spillage, and wax left in the pot

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 millilitres, 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 from the fragrance load, which is defined as a percentage of the finished candle (wax + fragrance), not of the wax alone: fragrance_total = wax_total × (load ÷ (100 − load)). At an 8% load, that is wax_total × 8 ÷ 92.

Limits: containers are assumed to be straight cylinders — tapered or irregular vessels will read slightly high. The 0.86 g/ml density is for soy wax as weighed solid; always weigh wax on a scale rather than scooping by volume.

How the soy wax calculation works

The calculator needs three numbers to size a batch: the container's inside diameter, the fill height (how high the wax will actually go, not the vessel's rim), and how many candles you are pouring. Everything else is arithmetic.

First it finds the container volume as a cylinder: V = π × r² × h, where r is half the diameter. Cubic inches are converted to millilitres (1 in³ = 16.387 ml), then to wax weight using soy wax's density of 0.86 g/ml. A millilitre of container space needs 0.86 g of solid soy wax.

That per-candle wax weight is multiplied by the candle count and increased by the waste margin — 10% is the usual default, covering shrinkage as the soy cools and the wax left clinging to the melting pot. Fragrance oil is the last step: the load percentage applies to the finished candle, so fragrance = wax × (load ÷ (100 − load)). At 8%, that is wax × 8 ÷ 92.

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. × 16.387 = 405.4 ml per candle.

Step 2 — wax per candle: 405.4 ml × 0.86 g/ml = 348.7 g of soy wax.

Step 3 — batch wax: 348.7 g × 4 candles = 1,394.8 g, plus 10% margin → 1,534.3 g of soy wax to melt.

Step 4 — fragrance oil: 1,394.8 g × 8% = 111.6 g of fragrance oil, dosed on the un-margined wax weight.

So weigh out 1,534.3 g of soy wax and 111.6 g of fragrance oil, and you will have enough for four candles of about 411.5 g of finished candle weight each. The calculator above does all four steps instantly for any vessel size.

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.

Related calculators

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. A 3-inch-wide, 3.5-inch-tall candle holds about 405 ml, which is roughly 349 g of soy wax. Multiply by your candle count and add a 10% waste margin.

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. An 8 fl oz vessel holds about 237 ml, which needs roughly 204 g of soy wax plus about 18 g of fragrance oil at an 8% load — so '8 oz' candles commonly use 200–210 g of wax.

What does an 8% fragrance load actually mean?

Fragrance load is fragrance oil as a percentage of the finished candle weight, so an 8% load on a 1,000 g batch of wax-and-oil means 80 g of oil. A very common beginner mistake is taking 8% of the wax weight instead — the difference is small but real: 1,000 g of wax at 8% load actually needs 87 g of oil (1,000 × 8 ÷ 92), not 80 g.

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?

The 0.86 g/ml figure is the density of solid soy wax — weigh your wax on a scale. Do not melt it and measure it in a jug: molten wax is less dense, so a millilitre of liquid wax weighs less than a millilitre of volume in the container, and you would under-fill.

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