How to · 8 min read

How to calculate wax and fragrance oil for any candle container

Work out exactly how much wax and fragrance oil a candle container needs, by percent of wax or total content, and what one candle really costs once breakage is counted.

Published 21 September 2026

Key takeaways

  • “8% fragrance” is two different recipes. Percent of wax: 100 g wax + 8 g oil. Total content: 92 g wax + 8 g oil in a 100 g candle. Use the method your supplier uses.
  • Weigh one real test pour. Filled candle minus empty jar is the fill weight, exact for your wax and your jar. Water weight × 0.86 is only an estimate.
  • Count the jars that break. 144 jars that make 130 candles cost 11% more per candle than the invoice says.
  • The free candle calculator does all three and keeps your numbers in your browser.

The same questions come up on r/candlemaking every week: whether 8% of 100 g means 108 g or 100 g, why the volume formula never quite fills the jar, and — the painful one — a maker who worked out they had been losing $3 on every candle for six months. All three are arithmetic, and all three are worth getting right once.

Is fragrance load a percentage of the wax or of the whole candle?

Both conventions are in use, by respected suppliers, and they give different answers.

  • Percent of wax (fragrance added on top): fragrance = wax weight × load. For an 8% load, 100 g of wax takes 8 g of oil and the candle weighs 108 g. Craftybase's calculator, for example, describes load as “the percentage of fragrance oil relative to the total wax weight”.
  • Total content: fragrance = finished candle × load. An 8% load in a 100 g candle is 8 g of oil and 92 g of wax. Candle Shack publishes a calculator named for this “total content method”.

On a 200 g candle at 10%, percent of wax gives 18.2 g of oil and total content gives 20 g. That is nearly two grams per candle, which across a batch of fifty is a lot of expensive oil and a noticeable difference in throw. Neither is wrong. What goes wrong is following a recipe written in one method with a calculator using the other.

How do you work out how much wax a container holds?

The quick estimate fills the jar with water to your fill line, weighs the water, and multiplies by a factor for your wax (about 0.86 is often quoted for soy). It is a fair first guess, and it drifts because waxes differ and the factor is an average.

The exact method takes one candle:

  1. Weigh the empty jar.
  2. Make one test candle with your wax and fragrance, poured to your fill line.
  3. Weigh it once it has set, and subtract the jar.

That number, the fill weight, is wax and fragrance together, for your wax, your jar and your fill line. Enter it in the candle calculator and it splits it into wax and oil by whichever method you choose.

What is the formula?

With the fill weight F and the load L as a fraction:

  • Percent of wax: wax = F ÷ (1 + L), fragrance = wax × L.
  • Total content: fragrance = F × L, wax = F − fragrance.

For a batch, multiply by the number of candles and add a few percent for the wax that stays in the pouring pitcher. Worked example, twelve 200 g candles at 8% by percent of wax with 3% spare: 185.2 g of wax and 14.8 g of oil each, so melt 2,289 g of wax and weigh out 183 g of oil.

What does one candle really cost?

The invoice costs are easy: wax and oil by weight, the jar, the wick, the label. The ones that sink margins are the ones the invoice does not show:

  • Breakage. Jars cracked on arrival, chipped on the bench, dropped in the sink. If a case of 144 yields 130 candles, each candle carries 144 ÷ 130 = 1.11 jars.
  • Testing. Every new scent, wick or wax costs candles nobody buys. Spread that over what you sell.
  • The small parts. Lid, warning label, box, tissue: each small, all on every candle.
  • Your time. Melting, pouring, topping up, labelling, packing.

The calculator's cost panel adds these line by line and shows the hidden part on its own, so you can see what breakage and testing cost per candle. Then take that total to the craft pricing calculator to set a price, and to the fee calculator to see what a sale leaves.

What fragrance load should you use?

Your wax's data sheet gives the maximum it holds, and your fragrance supplier may give a lower usage rate. Neither this post nor the calculator picks a number for you. The calculator warns above 12%, where many waxes start to sweat oil, and the rest is test burns.

Sources

Everything linked here is free to use, runs in your browser, and needs no account. If something in this post is wrong or out of date, it is worth telling us — the date at the top is the last time it was checked.