When making candles, one of the most important steps is calculating the amount of wax per candle. Unless you’re a math whiz, this can be a confusing and daunting part of the candle making process. Luckily, there is an easy process for determining how much candle wax you need per container!
The calculation in this article is not a standard mathematical formula. It is written out with detailed descriptions to make it easy for everyone to understand. Even if you’re not good with numbers, our formula will have you making perfectly measured candles in no time.
To determine how much wax you need per candle, you need to know these 4 things:
- How much water your candle container holds—by weight.
- The specific gravity of the wax you’re using (covered below).
- What percent of fragrance and other additives you want to use (i.e., fragrance load).
- How many candles you want to make.
You will need a digital scale to get an accurate calculation for the formula. Make sure you have a pen and paper for taking notes so that you can repeat your results. We also have this handy Candle Testing Note Sheet that has some extra room for jotting down notes!
Measuring by Weight
Before starting, it’s important to mention that all of our measurements will be taken by weight and not volume. Not only is measuring by weight more accurate, it’s also necessary for this formula. The reason is that wax is less dense than water. In other words, 1 pound of wax takes up more room than 1 pound of water. Therefore, you can’t simply fill a container with water to determine how much wax it holds. That would lead to a lot of leftover wax!
Basic Candle Wax Calculation Steps
Determining how much wax and fragrance you need for any candle container is an easy process. We cover all of these steps in more detail later in the blog if you want more information on the process. Here are the basic steps:
- Put the empty container on a kitchen scale and tare the scale to Zero. Set the scale to measure in grams or ounces.
- Fill the container with water to the same line that you would fill the container with wax when making a candle.
- Take note of the weight on the scale in grams or ounces.
- Multiply this number by 0.85 (you do this because wax is about 85% as dense as water on average – you can find specific gravities for each of our waxes in the section below).
- The number you get is the amount of wax that the container will hold in grams or ounces.
- If you are adding fragrance, multiply that number by 0.1 for a 10% fragrance load (or .06, .08, .09, .11, .12 etc. for a different fragrance load). The number you get is the weight of the fragrance you need. Subtract this number from your wax weight to get the total weight of wax you need when using fragrance.
- If making multiple containers, simply multiply your wax and fragrance amounts by the number of containers.
Example: If your container held 10 oz of water (by weight), you would multiply 10 x 0.85 to determine that the container would hold 8.5 oz of wax. To account for 10% fragrance, multiply 8.5 x 0.10 to get 0.85. Then subtract 0.85 from 8.5 to determine that you need 7.65 oz of wax and 0.85 oz of fragrance per container.
Detailed Wax Calculation Steps
If you want to dive deeper into the process, here is a more detailed explanation of the steps. This is the same process covered above, just more in depth.
Step 1: Determine How Much Water Your Container Holds
The first thing you need to do is check how much water will fit into your candle container. We are going to measure how much the water weighs, not now much volume it takes up. This information is needed to determine the amount of wax the container will hold in the end.
- Place an empty candle container on your digital scale and tare it to zero. For the most accurate results, we recommend setting the scale to measure in grams. If your scale doesn’t measure in grams, use ounces.
- Add water to the container, filling to the same level that you would fill it with candle wax (e.g., approx. 1/4 inch below the rim). Don’t fill the container all the way full.
- Take note of the measurement on the scale. This is how many grams (or ounces) of water your container holds by weight.
Step 2: Calculate the Specific Gravity of Your Candle Wax
Specific gravity refers to the density of a substance in relation to the density of water. Basically, it is a ratio that tells you whether something is more dense or less dense than water. As we mentioned before, wax is less dense than water. But for this part of the formula, we need to know exactly how much less dense it is.
Once you know the specific gravity of your wax, you will multiply the weight of the water that fits in your container by the specific gravity to get the wax you need per container.
Water has a density of about 1 gram per cubic centimeter, which essentially means that water takes up about the same amount of space whether you measure it by weight (grams or ounces) or by volume (ml or fluid ounces). This is not the case for wax.
Most candle wax is between 80% and 90% as dense than water. To illustrate what that means, imagine that you have two containers. If one were filled with 16 fluid ounces of water and the other were filled with 16 fluid ounces of melted wax, the container with water would hold 16 oz by volume, while the container with wax would hold 20 oz by volume (assuming the wax in question is 80% as dense as water).
You actually don’t need to know what all that means as long as you have a formula. We’re just explaining it for context.
What is the Specific Gravity of My Candle Wax?
If you’re using one of our waxes, we’ve calculated the specific gravity for you. No matter which wax you’re using, specific gravity is expressed as a decimal rather than a percent. For example, a wax that is 85% as dense as water has a specific gravity of 0.85.
Here are the specific gravities of our waxes:
- Ceda Serica specific gravity: .80
- CB2 specific gravity: .82
- EC-26 specific gravity: .83
- Soy Wax Flakes specific gravity: .84
- C55 specific gravity: .77
- Beeswax specific gravity: .90
If you are using a different kind of wax, 0.85 is the average specific gravity of candle wax. You can use 0.85 in your formula to get accurate results for most wax types.
Step 3: Adjust for Fragrance Load and Additives
Chances are, you’re adding fragrance to your candles. If so, you need to account for the weight of your fragrance oil when calculating how much wax to use in a candle container. If you are using other additives such as stearic acid, you need to account for that in your formula as well.
If you don’t include the weight of fragrance and additives in your formula, you will end up with leftover wax that doesn’t fit in your container. The excess might not be an issue if you’re making just one or two candles. However, failing to account for additives can create a huge amount of waste if you’re making a large batch of candles.
Start by deciding what fragrance load you want to use. Typical fragrance loads range from 6% to 12%, but you should always refer to your candle wax instructions to see the maximum fragrance you can use.
We highly recommend reading this article if you’re not familiar with fragrance loads.
Once you know the fragrance load, divide the number by 100 to convert the percent into a decimal. For example, an 8% fragrance load would be .08 as a decimal.
Next, multiply the fragrance load decimal number by the amount of wax per container. The resulting number is the amount of fragrance you need per container. Subtract the fragrance amount from the amount of wax needed per container to determine the adjusted amount of wax you need per container.
Note: If you are using additives (such as stearic acid), you will follow the same steps you did for the fragrance to adjust the wax amount accordingly. For example, if I want to use 2% stearic acid, I will multiply the wax per container by .02. I will then subtract the resulting number from the wax per container to get the adjusted amount. If you are using fragrance and additives, subtract the amount of both additives. You generally don’t need to account for colorants unless you are making a huge batch of candles in which colorants account for more than 1% of your total formula.
Step 4: Determine How Much Wax You Need for Multiple Containers
If you want to make just one candle, you have all the information you need and you’re ready to go. However, if you want to make a batch with multiple candles, you need to calculate the total amount of wax (and fragrance) you need for all of your containers.
This is easy. Simply multiply the wax per container by the number of containers. You will also multiply the amount of fragrance/additives per container by the number of containers. Be sure to subtract the fragrance/additives from the amount of wax needed. Once you have all this information, you are ready to go!
Testing Your Formula
If you’ve made it this far, you have all the info you need to pour your candles. We recommend making one test candle to check that your measurements are correct. This can help save you a lot of time and money by not using unnecessary supplies. After you’re sure the measurements are correct, you can make a larger batch with confidence!
Need more info on making and testing candles? We’ve got you covered with these articles!