Candle Flame Heat Output Calculator

How Much Heat Does a Candle Actually Put Out?

It sounds like a trivial question, but the answer is a genuinely useful energy-balance calculation - the same math engineers use for burners, just scaled down to something sitting on your table.

A typical paraffin candle burns somewhere around 5-8 grams of wax per hour, and paraffin wax carries a heating value of roughly 42-46 MJ/kg. Multiply those together (after unit conversion) and a single candle turns out to produce somewhere in the range of 40 to 100 watts of heat - noticeable in a small enclosed space, but nowhere near a space heater.

Try it yourself: enter a wax burn rate in grams per hour and a heating value in MJ/kg (43 MJ/kg is a reasonable default for standard paraffin) to see the wattage for your specific candle.

This is exactly why a room full of lit candles at a dinner party or ceremony can measurably warm the space over time, and why emergency preparedness guides sometimes mention candles as a minor supplemental heat source in a pinch (with the obvious fire-safety caveats).

Curious about a similarly small flame used for a practical purpose instead? See the Pilot Flame Heat Output Calculator.