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How much wax does a candle container need
Candle making looks simple until the wax runs out mid-batch, or a shelf of containers ends up half filled because the wax was guessed. The amount depends on the container size, the wax type and the number of candles, and the maths is easy once the formula is clear. This calculator turns container diameter, fill height, wax type and batch size into grams of wax per candle and for the whole batch, with a 10 percent extra allowance for the wax that stays in the pouring jug.
The maths starts with the cylinder volume: pi times the radius squared times the height. A container 8 centimetres across and filled 10 high holds about 500 millilitres before the fill adjustment, and the calculator uses 90 percent of the height by default, because candles are not filled to the brim. Multiply the volume by the wax density, about 0.9 grams per millilitre for soy and paraffin and 0.96 for beeswax, and the result is the wax weight per candle.
How to use the calculator
- Measure the inside diameter of the container in centimetres.
- Enter the height you will fill to, not the full container height.
- Enter how many candles you plan to make.
- Choose the wax type for the right density.
- Read the grams per candle and the batch total, then weigh the wax.
A worked example
Take a container 8 centimetres across, filled 10 high, in soy wax. The volume at 90 percent fill is about 452 millilitres, and at 0.9 grams per millilitre that is 407 grams of wax per candle. A batch of six needs 2,687 grams with the extra allowance, which is just over two and a half kilograms. Buying a two kilogram bag would leave the batch short, and that is exactly the shortage this calculator prevents.
Now try a small tin 5 centimetres across and 5 high. It needs under 90 grams per candle, so a single kilogram of wax makes about eleven of them. Small containers are efficient for testing new scents: a test batch of three tins uses under 300 grams, so a failed scent costs little.
Tips for clean candles
- Weigh wax, never measure it by volume. Flakes settle differently every time, but grams are grams.
- Melt a little extra and keep it warm for the second pour. Most candles need a top-up pour as the wax cools and shrinks.
- Match the wick to the container diameter. A wick that is too small leaves wax on the walls, and one that is too large burns too hot.
- Let candles cure for at least a day, and a week for soy, before judging the scent throw.
Common mistakes
The most common mistake is measuring the outside of the container instead of the inside. Thick glass can add half a centimetre on each side, which inflates the volume noticeably on small containers. Another mistake is forgetting the second pour: wax shrinks as it cools and leaves a dip around the wick, so the batch total must include the top-up wax, which the 10 percent allowance helps cover.
Another trap is filling to the brim. A candle filled to the edge spills when the wick is lit and the wax melts, and it leaves no room for the melt pool. Leave at least a centimetre of headroom, and use the fill height, not the container height, in the calculator.
Who uses a wax calculator
Home candle makers use it to buy the right bag size for a batch. Small sellers use it to cost candles, because wax is the largest ingredient cost. Workshop teachers use it to kit up classes without waste. Weigh the wax, fill with room to spare, and every container in the batch comes out even.