As a candlemaker, you should know how to calculate the burn time for your products. You’ll want to provide this information to your customers and make sure you are selling a long-burning, high-quality candles.
Candle Burn Calculations
There are several calculations you can do so you won’t have to burn your candle to understand its burn time. There are also different variables to consider when crafting your candles to ensure a long burn time.
As a general rule, smaller votive candles burn about 7 to 9 hours for each ounce of wax you use. Larger candles with long wicks burn wax at a much faster rate. A typical estimate for larger candles averages 5 to 7 hours for each ounce, giving a 12-ounce candle 60 to 84 hours of burn time.
However, you should calculate the burn time for your specific products. Use the following methods to determine your burn times for each candle size and style:
Take the initial weight
Using an accurate scale, take the measurement of the weight of an unburned candle. It is helpful to have a scale that measures in grams. If that’s not possible, your measurement should be to the nearest fraction of an ounce. This measurement will become your initial weight.
Do a burn test
Initially, you need to burn the candle for at least 4 hours to determine how much of the candle has burned in this time period. This calculation is referred to as the duration of test burn. You will need to conduct several burn tests until you achieve the point where the candle puts itself out.
Record the number of hours and the number of burn tests completed until the candle extinguishes itself. As an example, if it takes you 30 burns at 2-hour intervals to burn through all of the wax, your estimated burn time will be 60 hours.
It may also be helpful to burn two candles simultaneously at the same intervals to confirm results are consistent with each product.
Another weigh in
Once your candle has cooled, weigh it again and use the same units of measurement that you did in the first weight calculation to determine your final weight.
You will also need to weigh an empty candle container.
When your measurements are complete, subtract the final weight from your starting weight. You’ll then need to divide the total wax weight used in the candle (excluding the container) by the amount of wax used during your burn test to confirm your burn hours.
Candle Variables Make a Difference
The variables involved in candle making will make a difference in the burn times for candle products. Candle-specific variables may include:
- Candle size
- Type of waxed used
- Amount and type of additives used
- Type of wick material used
- Length of wick
- Use of odd-shaped glass candle jars
Another variable in your candle’s burn time concerns how hot the glass becomes while burning. Using a heat-safe glass for all candles is essential to preventing broken glass and candle-related fires.
Other factors in the environment also affect your candle’s burn time, including:
- Movement of air
- Amount of oxygen
- Room temperature
Burn times can be added directly to your candle product label. Providing your customers with the closest burn time estimate helps them to make buying decisions and gives them confidence in your products.