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Candle Wax Calculator
Use this free candle wax calculator to work out exactly how much wax and fragrance oil your batch needs. Enter the jar size, how many candles you are making, and how full you fill them, and the calculator gives you the wax weight in grams and ounces, the fragrance oil weight at your chosen load, the total pour weight, and how many wicks to buy. No more guessing, no more leftover wax — and no more running short mid-pour.
| Item | Amount |
|---|---|
| Wax per candle | 183.1 g |
| Fragrance oil (8%) | 58.6 g |
| Total pour weight | 791.1 g |
| Wicks needed | 4 |
How it works
Candle making has one confusing trap: jar sizes are given in fluid ounces, which measure volume, while wax is bought and weighed in ounces by weight — and the two are not the same. An 8-ounce jar holds 8 fluid ounces of water, but wax is less dense than water, so it holds only about 6.5 ounces of soy wax by weight. The calculator handles that conversion for you. It starts with the jar size in fluid ounces, multiplies by 29.57 grams per fluid ounce to get the weight of water that would fill the jar, multiplies by your fill percentage, and then multiplies by the wax density — 0.86 for soy wax — to get the wax weight for one candle. Multiply by the number of candles for the batch total.
The fill level matters because candles are never filled to the brim. A 90 percent fill is the standard: it leaves room for the wick and for the wax to expand slightly as it cools, and it leaves a clean rim that looks professional. An 80 percent fill is common for tins and for candles that will be sold with a lid, while 95 percent is used when the maker wants the biggest possible candle from a jar.
Wax density is different for every wax type, and the calculator includes the common ones. Soy wax is 0.86, which means it weighs 86 percent as much as the same volume of water. Paraffin is denser at 0.90, beeswax is denser still at 0.96, and coconut wax sits at 0.92. A soy-paraffin blend is about 0.88. Across a batch the difference adds up: the same four 8-ounce jars need about 732 grams of soy wax but about 767 grams of paraffin.
Fragrance oil is measured as a percentage of the wax weight, not of the total pour. This is called the fragrance load, and most waxes hold 6 to 10 percent. At an 8 percent load, 732.5 grams of wax needs 58.6 grams of fragrance oil. The total pour weight — wax plus fragrance oil — is 791.1 grams, which is the amount of liquid you will actually pour into the jars. Always check the maximum fragrance load for your specific wax before going above 10 percent: too much oil can cause the candle to sweat, smoke, burn poorly, or throw less scent rather than more.
Wicks are counted per candle, and the right number depends on the diameter of the jar. A jar up to about 3 inches across usually needs one wick. Jars 3 to 4 inches across often need two wicks, and jars over 4 inches across may need three, so that the melt pool reaches the edges. Always do a test burn with one candle before making a whole batch: light it, let it burn for 2 to 3 hours, and check that the melt pool reaches the edges without getting deeper than about half an inch.
Weighing is the habit that makes all of this repeatable. A kitchen scale that reads in grams is the single most useful tool in candle making, because grams are exact and they avoid the fluid-ounce versus weight-ounce confusion entirely. Write down the recipe the calculator gives you so you can reproduce the same candle batch after batch.
Fragrance oil = total wax × fragrance load % · Total pour = wax + fragrance oil
Worked example
You are making four candles in 8-ounce jars, filled to 90 percent, with soy wax and an 8 percent fragrance load, one wick each.
Step 1: Water weight of one full jar — 8 × 29.57 = 236.6 g.
Step 2: At 90 percent fill — 236.6 × 0.90 = 212.9 g of water.
Step 3: Wax per candle — 212.9 × 0.86 = 183.1 g of soy wax.
Step 4: Total wax — 183.1 × 4 = 732.5 g, or 25.8 oz.
Step 5: Fragrance oil — 732.5 × 0.08 = 58.6 g, or 2.1 oz.
Step 6: Total pour — 732.5 + 58.6 = 791.1 g. Wicks: 4 × 1 = 4.
Weigh out 732.5 grams of soy wax and 58.6 grams of fragrance oil, melt the wax, add the fragrance at the right temperature, and pour 791.1 grams of liquid into the four jars — about 197.8 grams per jar. Set one wick in each jar, let them cure for one to two weeks, then test burn one before selling or gifting the rest.
FAQ
How much wax do I need for an 8 oz candle?
An 8-ounce jar filled to 90 percent needs about 183 grams of soy wax, which is roughly 6.5 ounces by weight. Four of those candles need about 732 grams of wax in total. The exact amount depends on the fill level and the wax type, because different waxes have different densities.
How do you calculate candle wax weight?
Fill the jar with water to your fill line and weigh the water, or use the jar's fluid-ounce size times 29.57 grams per fluid ounce. Multiply that water weight by 0.86 for soy wax, which is less dense than water. That gives the wax weight for one candle; multiply by the number of candles for the batch total.
How much fragrance oil goes in a candle?
Most candle waxes hold a fragrance load of 6 to 10 percent of the wax weight. An 8 percent load on 732 grams of wax is about 59 grams of fragrance oil. Always check the maximum fragrance load for your specific wax, because too much oil can cause sweating, poor burning, or a weak scent throw.
Why is candle wax measured in grams, not ounces?
Jar sizes are given in fluid ounces, which measure volume, but wax is bought and weighed in ounces by weight, and the two are not the same. Wax is less dense than water, so 8 fluid ounces of jar space holds only about 6.5 ounces of soy wax by weight. Weighing in grams avoids the confusion entirely and gives exact, repeatable batches.
How many wicks does a candle need?
A jar up to about 3 inches across usually needs one wick. Jars 3 to 4 inches across often need two wicks, and jars over 4 inches across may need three. The right wick also depends on the wax type and the fragrance load, so always do a test burn and check that the melt pool reaches the edges within about 2 to 3 hours.