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Candle burn time.

Weigh the candle, burn it for a few hours, weigh it again, and you know its burn rate. Enter the wax weight and the rate to get total hours, 3-hour burning sessions, cost per hour and days at your daily use. Runs in your browser.

Your candle

Weight unit

Wax weight The net weight printed on the label. Check it matches the unit you picked.

Wax you will leave in the jar (optional) Same unit as above. The National Candle Association says to stop burning when 1/2 inch of wax remains, so enter the wax below that line.

Burn rate (grams per hour) Measure it below, or type a rate you already know. 6 g/h is an example, not a standard.

Optional: candle weight before a test burn (g)

Weight after the test burn (g)

Hours burned in the test If all three are filled, the measured rate replaces the burn rate above. Weigh the whole candle on a kitchen scale.

Candle price (optional)

Hours you burn it per day (optional)

Burn time

Fill the form and press Calculate.

Worked example

An 8 oz candle holds 8 x 28.3495 = 226.8 g of wax. Say you weighed it before and after a 3-hour burn and it lost 18 g: the burn rate is 18 / 3 = 6 g per hour. Burn time is 226.8 / 6 = 37.8 hours, which is 13 sessions of up to 3 hours. At $28 that is 28 / 37.8 = $0.74 per hour, and at 2 hours a day it lasts about 18.9 days.

How it works

Burn rate (g/h) = grams lost / hours burned. Burn time = (wax weight - wax left) / burn rate. Cost per hour = price / burn time. 1 oz = 28.349523125 g. The burn rate depends on the wax, wick, container width and fragrance load, which is why this tool asks you to measure it rather than assume one.

What this is not. Weigh over a normal 2 to 3 hour session so the test looks like how you really burn it. Jar and wick weight are not part of the wax, so weigh the candle before and after on the same scale and use the label wax weight for the total. Never leave a burning candle unattended.

Sources and basis: National Candle Association, How to Candle: Tips and Tricks (three hours at a time) (opened 8 October 2026); National Candle Association, Candle Safety Tips (trim the wick to 1/4 inch) (opened 8 October 2026).

FAQ

How long does a candle burn per ounce?

It depends on the candle, so measure it. A rate of 6 g per hour gives about 4.7 hours per ounce of wax (28.35 / 6). Your candle may burn faster or slower.

How do I find my candle's burn rate?

Weigh the candle on a kitchen scale, burn it for 2 to 3 hours, let it cool and weigh it again. Grams lost divided by hours burned is the rate; enter the three numbers above.

How long should I burn a candle at one time?

The National Candle Association says not to burn a candle for more than three hours at a time. The session count above uses 3 hours.

Why is the burn time on the label different from mine?

A label time is the maker's estimate. Your own burn rate, found by weighing, is the better number for your candle.

Disclaimer

Never leave a burning candle unattended and keep it away from anything flammable. The National Candle Association advises not to burn candles all the way down and to stop when 1/2 inch of wax remains. Burn times are estimates from the rate you enter or measure.