How to calculate burn time of a candle: You do not have to burn an entire candle to calculate its burn time accurately. The burn time of any candle can be calculated using the simple formula: Total weight of the candle / burn rate = burn time. Or, TW / BR = BT ("/" here is "divided by") If you are calculating the burn time of a non-container candle, total weight (TW) is derived simply by weighing the candle. If you are calculating the burn time of a container candle, you must account for the weight of the container itself, in order to be completely accurate in your calculation. Before you pour, weigh the container. Weigh the container again, after pouring and complete cooling of the candle. Subtract the empty container weight from the finished container candle weight, and this new weight is your total weight (TW) of the actual candle. Basically, Finished candle weight - empty container weight = total weight Once you have your total weight, burn the candle for one hour. Weigh the candle again to get a new total weight. Subtract your new total weight from the original weight to calculate how much the candle burned in the one hour. Original Total weight - New total weight = amount burned in one hour. The difference between the two is your burn rate. Next, plug the original total weight into the formula, and you will have your estimated burn time. An example: Assume that we have a container that weighs .5 oz. After pouring, the entire candle weighs 16.5 oz. Finished candle weight - empty container weight = total weight So, 16.5 oz. - .5 oz. = 16 oz. The total weight is 16 oz. After burning for one hour, we weigh again, and the candle weighs 16.3 oz. Original Total weight - (New total weight -jar weight) = amount burned in one hour. So, 16 oz. - (16.3 oz. - .5 oz.) = .3 oz. Our burn rate is .3 oz. per hour. Since Total weight of the candle / burn rate = burn time. 16.0 (note NOT 16.5) / .3 oz. = 55 The burn time of our container candle would be 55 hours. Note how the weight of the jar was subtracted from both the pre- and post-burn weights. This extra step is essential for complete accuracy. A non-container example. Assume that we have a votive candle that weighs 2 oz. After burning for one hour, we weigh again and the votive weighs 1.8 oz. Original Total weight - New total weight = amount burned in one hour. So, 2 oz. - 1.8 oz. = .2 oz. Our burn rate again is .2 oz. per hour. Since Total weight of the candle / burn rate = burn time. 2 oz. / .2 oz. = 10 hours The burn time of our votive candle would be 10 hours. |