Start With Container Volume
Knowing how much wax a candle needs comes down to two numbers: how many fluid ounces your container holds up to the fill line, and how much one fluid ounce of your wax weighs. Wax sold by the pound is measured by weight, while containers are measured by volume, so you need a conversion between the two.
The MakersMath Candle Wax Calculator uses one planning figure for soy wax: wax weight (oz) = container volume (fl oz) x 0.86. There is no extra shrinkage multiplier in that formula. This guide uses the same math so the two always agree.
What the 0.86 Figure Is
0.86 is the specific gravity used for soy wax in the calculator. Specific gravity is a ratio to water, so it has no unit of its own. Other waxes have different values, and the figure shifts with temperature, so check the technical data sheet or SDS for your wax. This guide does not list densities for other waxes because we have not verified them against supplier documents.
Treat 0.86 as a planning number. Weigh the wax that fills your first test jar and adjust if your result differs.
The Water-Fill Method
- Fill the empty container with water to the height you want the wax to reach, usually a little below the rim.
- Pour the water into a measuring cup and read the volume in fluid ounces.
- Multiply by 0.86 to get ounces of soy wax.
Example: a jar that holds 10 fl oz of water to the fill line needs 10 x 0.86 = 8.60 oz of soy wax.
If you only have dimensions, a round container's volume in cubic inches is pi x radius x radius x fill height. One cubic inch equals 0.5541 fl oz (231 cubic inches per US gallon, 128 fl oz per gallon).
| Round container (diameter x fill height) | Volume | Fl oz | Soy wax (oz) | |---|---|---|---| | 2.5 in x 3 in | 14.73 cu in | 8.16 | 7.02 | | 3 in x 3 in | 21.21 cu in | 11.75 | 10.11 | | 3.5 in x 3 in | 28.86 cu in | 15.99 | 13.75 | | 4 in x 4 in | 50.27 cu in | 27.85 | 23.95 |
Wax Weight by Container Size
All values come from fl oz x 0.86, with ounces converted to grams at 28.3495 g per ounce.
| Container fill volume | Soy wax (oz) | Soy wax (g) | |---|---|---| | 4 fl oz | 3.44 | 97.5 | | 6 fl oz | 5.16 | 146.3 | | 8 fl oz | 6.88 | 195.0 | | 10 fl oz | 8.60 | 243.8 | | 12 fl oz | 10.32 | 292.6 | | 16 fl oz | 13.76 | 390.1 |
A jar sold as "8 oz" is often labeled by wax weight or by fill, not by its water capacity, so measure yours with the water-fill method instead of trusting the label.
Fragrance Oil on Top of the Wax
On MakersMath, fragrance load is a percentage of the wax weight. The oil is added in addition to that wax, so the finished candle weighs wax plus oil.
| Container fill volume | Wax (oz) | FO at 6% (oz) | FO at 8% (oz) | FO at 10% (oz) | |---|---|---|---|---| | 4 fl oz | 3.44 | 0.21 | 0.28 | 0.34 | | 6 fl oz | 5.16 | 0.31 | 0.41 | 0.52 | | 8 fl oz | 6.88 | 0.41 | 0.55 | 0.69 | | 10 fl oz | 8.60 | 0.52 | 0.69 | 0.86 | | 12 fl oz | 10.32 | 0.62 | 0.83 | 1.03 | | 16 fl oz | 13.76 | 0.83 | 1.10 | 1.38 |
If instead you need a finished candle of 10 oz total weight with a 10% load on the wax, the wax is 10 / 1.10 = 9.09 oz and the oil is 0.91 oz. See the fragrance load guide for how to choose the percentage.
Worked Example: Twelve Candles
You are pouring twelve candles, each filled to 8 fl oz.
- Wax per candle: 8 x 0.86 = 6.88 oz
- Twelve candles: 6.88 x 12 = 82.56 oz
- Melting-pot allowance of 15% (a rule-of-thumb buffer, not a measured figure): 82.56 x 1.15 = 94.94 oz
- In pounds: 94.94 / 16 = 5.93 lb
Wax clings to the pot, spoon and pouring pitcher, so some allowance above the calculated amount is sensible. Adjust the percentage after you see how much your own setup loses.
Worked Example: A Hundred-Candle Order
For 100 candles at a 10 fl oz fill:
- 10 x 0.86 = 8.60 oz each
- 8.60 x 100 = 860 oz = 53.75 lb before any pot allowance
Wax Cost Per Candle
Use your own wax price instead of a guessed one:
Wax cost per candle = (wax oz / 16) x your price per pound
A 6.88 oz fill uses 6.88 / 16 = 0.43 lb of wax, so multiply 0.43 by whatever you pay per pound. For the full cost picture, see the candle making cost calculator.
Things That Change the Amount
- Container shape. Tapered or irregular containers do not follow the cylinder formula, so use the water-fill method.
- Wicks and additives. Wicks, wick stickers and dye take up very little space, but not zero. Re-measure with your actual setup.
- Settling and top-offs. Many waxes pull away as they cool and need a second pour. Keep a little extra wax aside for that. The amount depends on your wax and pour temperature, so check your wax maker's instructions.
- Wax type. The 0.86 figure is the calculator's soy planning number. For other waxes, check the supplier's data sheet.
Common Mistakes
Judging by the label
A jar labeled "8 oz" may not hold 8 fl oz of wax to the fill line. Measure it.
Confusing weight and volume
Fluid ounces measure volume; the wax you buy is sold by weight. That is why the 0.86 conversion exists.
Pouring one test jar and scaling blindly
Pour a test jar, weigh the wax actually used, and use that figure for the batch.
Key Takeaways
- Wax (oz) = container volume (fl oz) x 0.86, matching the calculator
- Measure volume with the water-fill method, not the jar label
- Fragrance oil is a percentage of the wax weight, added on top
- Add a pot allowance for batches, and tune it from your own results
- Pour a test jar and weigh it before scaling up
Ready to run your own numbers? Try our free Candle Wax Calculator and enter your container volume.