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Candle Burn Time Calculator
Use this free candle burn time calculator to find out how long a candle will last before you make it or buy it. Enter the wax weight, pick the wax type and wick size, and give the jar diameter. The calculator works out the total burn time in hours, the hours per ounce, the burn rate, and how long the first burn should be to stop the candle tunneling.
Weigh the wax, not the finished candle: the jar, wick, and fragrance add weight that never burns.
| Amount | Value |
|---|---|
| Burn rate | 0.11 oz per hour |
| Total burn time | 72.7 hours |
| Hours per ounce | 9.1 hours |
| Burn time in days (4 hrs/day) | 18.2 days |
| First burn (full melt pool) | 3 hours |
| Max burn per session | 4 hours |
How it works
A candle burns wax at a fairly steady rate, so its burn time is simply the wax weight divided by the burn rate. The burn rate depends on three things: the wax, the wick, and the jar. This calculator starts with a base rate for the wax, adjusts it for the wick, adjusts it again for the jar size, and then divides the wax weight by the result.
The wax sets the base rate. Beeswax burns the slowest at about 0.09 ounces per hour, soy burns at about 0.11 ounces per hour, and paraffin burns the fastest at about 0.13 ounces per hour. These are typical rates for a well-made container candle with a matched wick; a candle loaded with fragrance oil burns a little faster, and a candle with a poor wick burns unevenly no matter what the wax is.
Burn rate = wax rate × wick factor × jar factor
Wick factors: small 0.85 · medium 1.0 · large 1.2
Burn time = wax weight ÷ burn rate
Hours per ounce = 1 ÷ burn rate
The wick sets the size of the flame, and the flame sets how fast wax melts. A medium wick is the reference at a factor of 1.0. A large wick burns about 20 percent faster, a factor of 1.2, so the same candle lasts about a fifth less time. A small wick burns about 15 percent slower, a factor of 0.85, but only if it is still big enough for the jar: a wick too small for a wide jar never melts the wax to the edges, and the candle tunnels down the middle, leaving a ring of wax that never burns.
The jar matters because a wider jar has a bigger melt pool and burns more wax per hour. The calculator uses a jar factor of 1 plus 5 percent for every inch of diameter over 3 inches: a 3 inch jar has a factor of 1.0, a 4 inch jar has a factor of 1.05, and a 5 inch jar has a factor of 1.10. A very narrow jar under 3 inches gets a slightly smaller factor, because its small melt pool burns more slowly.
Two more numbers come out of the same calculation. Hours per ounce is one divided by the burn rate, and it is the fairest way to compare two candles of different sizes: a candle at 9.1 hours per ounce lasts longer per dollar of wax than one at 7.7 hours per ounce. The first burn guidance is one hour per inch of jar diameter, so a 3 inch jar needs about 3 hours on its first burn to open a full melt pool, and the maximum safe burn per session is 4 hours, however big the jar is.
Worked example
You pour an 8 ounce soy candle with a medium wick in a 3 inch jar.
Step 1: Base wax rate — soy burns at 0.11 oz per hour.
Step 2: Wick factor — a medium wick is 1.0, so the rate stays 0.11 oz per hour.
Step 3: Jar factor — a 3 inch jar is the reference size, so the factor is 1.0 and the rate stays 0.11 oz per hour.
Step 4: Total burn time — 8 ÷ 0.11 = 72.7 hours.
Step 5: Hours per ounce — 1 ÷ 0.11 = 9.1 hours per ounce.
Step 6: First burn — 3 inches × 1 hour per inch = 3 hours for a full melt pool.
The result is a total burn time of 72.7 hours, or 9.1 hours per ounce, with a 3 hour first burn. The same 8 ounces in paraffin would last about 61.5 hours, and in beeswax about 88.9 hours.
FAQ
How long does an 8 oz candle burn?
An 8 ounce soy candle with a medium wick in a 3 inch jar burns for about 73 hours, or about 9.1 hours per ounce. The same candle in paraffin burns about 62 hours, and in beeswax about 89 hours, because beeswax burns more slowly. A large wick burns the wax faster and shortens the time by about 20 percent, while a small wick stretches it by about 15 percent.
Which wax burns the longest?
Beeswax burns the longest of the common candle waxes, at about 0.09 ounces per hour, followed by soy at about 0.11 ounces per hour and paraffin at about 0.13 ounces per hour. Beeswax is also the most expensive and the hardest to work with, because it needs a hotter melt and a larger wick. Soy is the usual compromise: it burns almost as long as beeswax, costs much less, and holds fragrance well.
Does wick size change burn time?
Yes, a lot. The wick sets the size of the flame, and the flame sets how fast the wax melts. A large wick burns about 20 percent faster than a medium wick, so the same candle lasts about a fifth less time. A small wick burns about 15 percent slower, but if the wick is too small for the jar, the melt pool never reaches the edges, the candle tunnels, and wax is left stuck to the sides.
Why does my candle tunnel, and how do I fix it?
Tunneling happens when the first burn is too short: the melt pool only opens in the middle, and every later burn follows the same narrow tunnel, leaving a ring of wax on the sides. Fix it by burning the candle long enough on the first use, about one hour per inch of jar diameter, so the melt pool reaches the edges. For a candle that has already tunneled, wrap foil around the top with a small opening and burn it for an hour or two so the trapped wax melts down.
How long should I burn a candle at one time?
Burn a candle for about one hour per inch of jar diameter each time, and never more than four hours at a stretch. A 3 inch jar needs about 3 hours to reach a full melt pool. Shorter burns cause tunneling, and longer burns overheat the jar, smoke, and waste wax. Always trim the wick to about a quarter inch before lighting, keep the candle away from drafts, and never leave a burning candle unattended.