# Candle Burn-time Calculator

Generally, smaller candles such as votives with smaller wicks will burn at a rate of 7-9 hours per ounce of wax used. For example, a two ounce votive may be expected to burn for 14-18 hours. Larger candles with larger wicks will consume wax at a faster rate. The larger wicks can be expected to yield 5-7 hours per ounce of wax used. So, a 16 ounce canning jar, which actually holds only about 12 ounces of wax (by weight), could be expected to burn anywhere from 60-84 hours.

There are many variables that will affect the actual burn time of your finished candles; the type of wax used, the additives used, the type of wick used, etc. With so many variables, an actual burn test is often required to get an accurate estimate of the burn time of your candles.

Here is a calculator that will allow you to find a very close estimate of the total burn time of a candle, without actually having to burn it for the entire duration. You’ll still have to burn it for a few hours though, and you will need to record a few measurements.

You’ll need a fairly accurate scale for this. Postal scales work fine.

1. First, measure the initial weight of your unburned candle. If your scale allows it, make all your measurements in grams. Otherwise, measure to the nearest fraction of an ounce. This is your initial weight.

2. Next, burn your candle for 3 or 4 hours. You may wish to repeat the burn cycle several times. Record the total time that you burned your candle. This is your duration of test burn.

3. Now measure the weight of your candle again using the same units that you did above (grams or ounces). This is your final weight.

4. If you are using a container, measure the weight of the empty container. This is your empty container weight.

5. Enter the values and click Calculate

[insert_php]

echo ‘

‘;

//outputs the first box and it’s value
echo ‘
‘;
echo ‘ Initial Weight Enter the initial weight of the candle in ounces or grams. Use decimals if needed, for instance ten and a quarter ounces would be entered as 10.25 Do not type in any words such “grams”

‘;
//outputs the second box and it’s value
echo ‘ ‘;
echo ‘ Duration of Test Burn Enter the number of hours that the candle was burned. Use decimals if needed. 4 hours and 15 minutes would be entered as a decimal of 4.25

‘;
//outputs the third box and it’s value
echo ‘ ‘;
echo ‘ Final Weight Enter the final weight of the candle.

‘;
//outputs the fourth box and it’s value
echo ‘ ‘;
echo ‘ Empty Container Weight If this is a container candle, enter the weight of the empty container. If this is not a container candle, enter 0.

‘;
//outputs the ans box and it’s value
if ((\$_GET[‘fst_num’])-(\$_GET[‘thd_num’]) == 0)
{\$_GET[‘ans_num’]=’values needed’;}
else{
\$_GET[‘ans_num’]=((\$_GET[‘snd_num’])/((\$_GET[‘fst_num’])-(\$_GET[‘thd_num’])))*((\$_GET[‘fst_num’])-(\$_GET[‘frt_num’]));}

echo ‘ = ‘;
echo ‘ estimated total burn time in hours
‘;
echo ‘

‘;
[/insert_php]

###### 3 comments on “Candle Burn-time Calculator”
1. angle says:

If I were to do an experiment on how fast it would take a scented vs unscented candle, where would I find primary resources?

• Alan Wallace says:

I think the difference would usually be insignificant enough to reliably detect. In addition, I would expect the influence to vary a bit from scent to scent. There is only one way to really find out though, and that would be to make a few candles and do a burn test. This would probably make a good science fair project.

2. Anne says:

Thank you for your calculator – it’s awesome! I ran it a few times with my same candle batch and it worked great. My soy candle – 33 hours of burn time!

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