Candle Burn Time Calculator

Estimate how many hours your candle will burn based on its wax weight and burn rate.

How it is calculated

Burn time is the wax you have divided by how fast it burns: hours = wax weight (g) ÷ burn rate (g/h). The tool also divides the total by 4 hours and rounds down to get the number of full four-hour sessions: sessions = ⌊ hours ÷ 4 ⌋. Total time is shown with one decimal. The burn rate is the number you must supply and depends on wick size, wax type and drafts; to measure it, weigh the candle, burn it for a known time and divide the lost grams by the hours. Both inputs must be above zero.

Worked example

A 200 g candle that burns 5 g per hour. Total = 200 ÷ 5 = 40.0 h. Sessions of 4 hours = 40 ÷ 4 = 10 full sessions, so the candle lasts ten evenings if you burn it four hours at a time.

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Common mistakes

  • Entering the weight of the whole candle including the glass jar; only the wax counts.
  • Using a burn rate per minute or in ounces while the wax is in grams.
  • Taking a manufacturer's rate as fixed; drafts, a long wick or the first burn of a new candle change it.
  • Burning for short sessions of under about an hour; the extra wasted wax and tunnelling make real life shorter than the figure.
  • Reading the session count as the exact number of nights when sessions of other lengths are planned; it is only based on 4 hours.

About this calculator

Total burn time is estimated as wax weight ÷ burn rate (grams per hour), where burn rate depends mainly on wick size and wax type — a thicker wick or softer wax (like soy or paraffin blends) melts and consumes wax faster than a thin wick in a harder wax such as beeswax.

Candle makers use this to label expected burn time on a new product and to compare how a wick change affects it before a full burn test, while shoppers and hobbyists use it to estimate how long a candle will actually last based on its listed wax weight, since burn rate — not just size — is what really determines candle life.

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