Candle Wax Calculator

Work out exactly how much wax to melt. Enter the water capacity of your container and how many candles you are making; the calculator converts to wax weight, adds a little for pour loss and tells you how much fragrance oil to weigh out.

Why candle wax is measured by weight

Candle makers weigh wax rather than measuring it by volume, because solid wax flakes or pellets pack loosely and change volume as they melt. The container, however, is usually described by volume: an “8 oz jar” often holds about 8 fluid ounces of water, but wax is lighter than water, so it holds only around 7 ounces of wax by weight. The calculator bridges that gap. Fill your container with water to the level where the wax will stop, measure that water — by volume or by weighing it — and the calculator converts it to the weight of wax.

The formula

1. Water capacity in grams (1 ml of water weighs about 1 g; 1 US fl oz is 29.57 ml).
2. Candle blend per container = water capacity × wax density factor. Most container waxes are about 0.86–0.9 times the density of water; beeswax is denser, around 0.96.
3. Batch blend = blend per container × number of candles × (1 + pour-loss allowance).
4. Wax = batch blend ÷ (1 + fragrance load). Fragrance = batch blend − wax.

Calculating the fragrance as a percentage of the wax weight is the most common convention among candle makers and fragrance suppliers. Some makers use a percentage of total weight instead; the difference is small at typical loads but worth knowing when you compare recipes.

Worked example

Six jars each hold 8 US fl oz of water to the fill line — about 237 ml. With soy wax at a factor of 0.86, each jar takes about 203 g of wax and fragrance combined. Six jars need 1,221 g, and adding 5% for pour loss and a top-off pour gives about 1,282 g. With an 8% fragrance load, that is 1,187 g of wax (about 2.6 lb) and 95 g of fragrance oil (about 3.4 oz). Weigh both on a digital scale.

Measuring container capacity

• Place the empty container on a kitchen scale and tare it to zero.
• Fill it with water to where the wax surface will be — usually about half an inch (1–1.5 cm) below the rim.
• Read the weight in grams or ounces; that is the water capacity by weight.
• Dry the container completely before pouring wax; water causes spitting and poor adhesion.
• If all your containers are identical, measure one; if they vary, measure a few and use the average.

Pour loss and top-offs

Some wax always stays in the pouring pitcher, on thermometers and on spills, and many waxes sink around the wick as they cool, needing a small second pour to level the surface. Adding 5–10% to the batch covers this. Making extra and pouring the remainder into a small tin or wax-melt clamshell is better than running short mid-pour, when the last candle would have a different temperature and fragrance mix.

Choosing a fragrance load

Fragrance load is the amount of fragrance oil relative to wax. Most container waxes hold between 6% and 10%; some accept up to 12%. More fragrance does not always mean a stronger scent throw — overloading can cause oil to seep, poor burning and soot. Check the maximum on your wax's technical data sheet and the fragrance supplier's recommended maximum for candles, and use the lower of the two. For a new wax and fragrance pairing, test at a few loads, such as 6%, 8% and 10%, and compare after a full cure.

Typical wax and container figures

Melting and pouring basics

Melt wax in a double boiler or dedicated wax melter, never directly over a flame, and use a thermometer. Add fragrance at the temperature your wax supplier recommends — often around 185 °F (85 °C) for soy — and stir gently for a couple of minutes so it binds with the wax. Let the wax cool to the pouring temperature on the data sheet before pouring. Keep a fire extinguisher suitable for grease fires nearby, never leave melting wax unattended, and let candles cure for the recommended time — often one to two weeks for soy — before test-burning.

Wick sizing and test burns

The wick matters as much as the wax amount. A wick that is too small tunnels down the middle; one that is too large produces a tall flame, soot and a container that gets too hot. Wick suppliers publish charts by container diameter and wax type, but every wax, fragrance and dye combination behaves a little differently, so test-burn before selling or gifting. Burn a test candle for about one hour per inch of diameter on the first light so the melt pool reaches the edge, and keep notes of wick, load and results in a batch log.