Formulas used in candle making

Do you want to know how to figure out how much wax you will need? Do you want to know how to figure out how much scent your candle will need? Do you know how to determine a candle’s burn time? Details inside!
It’s time to put on our thinking caps and do some math! Remember geometry class and all of those strange formulas? It’s time to use them. I will tell you how to figure out how much wax you will need for your candles.

How to figure out how much wax your going to need.

First we will calculate a square or rectangle candle. We need to determine the volume of the shape. You simply multiply the height by the width by the length. This will tell you how many cubic inches that space occupies.

Let’s say we have a square candle that is 4 inches high, 4 inches wide and 4 inches thick.

We would multiply the width, times the height, times the depth or thickness. So it would look like this. 4 x 4 = 16, then multiply 16 x 4 = 64.

64 what? 64 cubic inches. That doesn’t seem to help does it, does it?

Okay in general, wax is 29.6 cubic inches per pound. So now we need to divide 64 (our total cubic inches ) by 29.6 ( the amount of cubic inches in a pound of wax ) and we get 2.02 pounds or just over 32 ounces.

Confused yet?

The formula for a cylinder or round pillar candle is even better. The formula is Pi times radius squared times height. I am getting a headache.

Okay back to school.

Pi = 3.14

Radius = half of the diameter or width of the candle.

So if we have a round cylinder pillar that is 4 inches tall and 4 inches in diameter, we would multiply 3.14 ( Pi ) times the radius squared. Remember the radius is half of the diameter, which was 4 inches. So half is 2.

We multiply 2 x 2 = 4. This is the radius squared.

Then we multiply 3.14 x 4 = 12.56.

We now take that 12.56 and multiply it by the height which was 4.

12.56 x 4 = 50.24. So this candle takes up 50.24 cubic inches.

Remember wax is 29.6 cubic inches per pound. So now we divide 50.24 by 29.6 and we get 1.69 pounds. Whew! That was easy. NOT!

Okay now that I have put you through basic geometry again, I will show you the easy way to figure out how much wax you need. That’s right the easy way.

You will need a digital scale for this method.

Weigh your mold.

Fill your mold with water and weigh it again. Subtract the weight of the mold from the weight of the mold full of water and you have exactly how much wax is needed.

For instance this silicone mold weighs 1 pound. We fill it with water and now it weighs 3 pounds. So the difference is 2 pounds, that’s how much wax is needed.
Much easier!

Always use an ounce or two more wax than is required. If you come up short you will have a hard time matching the color. If you have a little more your okay. Remember too that most wax shrinks when it melts. So it will appear that you have quite a bit of wax left over. This is needed for the second pour or Repour.

Questions and comments are welcomed!