🧵 Wick Sizing Reference Chart
A general starting-point reference for wick sizing by container diameter. Wick choice also depends on wax type and fragrance load — always do a test burn before finalizing your wick choice.
Diameter picks the row, wax picks the wick
The chart is indexed on the inside diameter of the vessel, from under 2 in (CD-6 to CD-8) up to 5 in and over, where one wick can no longer reach the glass. Diameter alone does not finish the job: a soy candle usually needs a larger wick than paraffin of the same width, because soy is slower to draw, and dye and a heavy fragrance load slow it further.
Running the test burn
- Cure first. Give the candle several days to a fortnight; testing one poured yesterday tells you little.
- Burn 4 hours with the wick trimmed to 6 mm. The melt pool should reach the glass and stand 6 to 13 mm deep. Reaching the edge inside 2 hours means the wick is too large.
- Watch the flame and the glass. A mushrooming, sooty flame, or a jar too hot to pick up, says size down. A ring of unmelted wax says size up.
Above about 4 in, split the work: two wicks in a 4 in jar are each sized for roughly a 2 in container and set either side of the centre, which melts the surface evenly instead of drilling a crater down the middle.
Frequently asked questions
What size wick do I need for a 3 inch jar?
Start around CD-12 to CD-14. A 3 in diameter sits on the boundary between two rows of the chart, so pour one of each and compare the melt pool after a 4 hour burn.
Why is my candle tunnelling?
The wick is too small for the diameter, or the first burn was cut short before the pool reached the edge. Wax remembers that first burn, so always give a new candle a full 3 to 4 hours.
When should a candle have two wicks?
Once the container passes about 4 in across. A single wick large enough to melt that width burns hot and sooty, while two smaller wicks share the surface and keep the flames modest.