How to Choose the Right Candle Wick Size

The wick is the smallest part of a candle and the one most likely to ruin it. Too small and it tunnels a hole straight down the middle; too big and it smokes, mushrooms, and overheats the vessel. Getting it right isn't luck — it's a size chart and one test burn. This guide shows you how to pick a wick by your candle's diameter, adjust for your wax, and read the first burn to know you nailed it.

How do you choose the right candle wick size?

Choose a wick by your candle's diameter first, then adjust up for waxes and additives that burn cooler. The wider the candle, the more heat the wick must throw to melt wax all the way to the edge. Start with the chart below, then fine-tune with a test burn.

Wick packaging lists the diameter range each size suits — match it to your jar or mold and you're most of the way there. For the molded shapes you'll be wicking, browse our candle molds collection.

What are the types of candle wicks?

The main wick types are cotton flat-braid, cored cotton, wooden, and hemp — each burns a little differently. Cotton is the reliable default; wooden wicks give a wider flame and a gentle crackle. Here's how they compare.

For a first candle, a cotton flat-braid or cored cotton wick with a metal base is the easiest to work with — it stands straight and centres without a fuss.

Does your wax and fragrance change the wick you need?

Yes — soy, heavy fragrance, and dark dye all call for a larger wick than the diameter alone suggests. These burn cooler or thicker, so they need more heat to melt cleanly. Under-wick them and even a correctly measured candle will tunnel.

• Soy and natural waxes: size up, since they burn cooler than paraffin.
• High fragrance load (8–10%): size up, since oil thickens the melt.
• Dark or heavy dye: size up slightly for the same reason.
• Paraffin, low scent: the chart size is usually spot on.

Your wax choice and wick choice go hand in hand — if you haven't settled on a wax yet, our guide on candle wax types explains how each one burns.

How do you know if your wick is the right size?

Do a test burn: the right wick melts wax edge to edge within a couple of hours, with a steady flame and no soot. This is the only way to be certain, because wax, fragrance, and mold all interact. Burn a test candle and watch for these signs.

1. Burn for 1 hour per 2.5 cm (1 in) of diameter on the first burn.
2. Check the melt pool. It should reach the edges and be about 1 cm deep — not tunnelling, not swimming.
3. Watch the flame. A calm 2–3 cm flame is right; a towering, flickering, or sooty flame means the wick is too big.
4. Adjust and retest. Size up if it tunnels, down if it smokes, then burn another test.

What goes wrong with the wrong wick size?

The wrong wick size shows up fast, and the symptom tells you which way to adjust. Match what you're seeing below.

My first soy pillar tunnelled no matter how patiently I burned it — the wick was simply one size too small for a wax that burns cool. Sizing up once fixed it, and the next candle burned clean to the edge. When in doubt, go one size larger for soy.

How do you centre and secure the wick?

Centre the wick before you pour and hold it straight while the candle sets. A wick that drifts off-centre burns unevenly and can scorch the mold or jar wall. It takes ten seconds and saves the whole candle.

1. Anchor the base. Thread the wick through your mold's centre hole, or stick a metal-base wick to the bottom of a jar with a dab of hot glue or a wick sticker.
2. Hold it straight. Rest a wick pin, wick holder, or two chopsticks across the top to keep it centred and taut.
3. Pour, then leave it. Don't nudge the wick while the wax sets.
4. Trim to 5–6 mm once the candle is fully firm.

For the full molded workflow around this — wicking, pouring, cooling, and demolding — see our guide on making candles in silicone molds.

Frequently Asked Questions

How do you choose the right size candle wick?

Choose the wick by your candle's diameter first: a small wick up to about 5 cm, medium for 5 to 7.5 cm, and large for 7.5 to 10 cm, with multiple wicks beyond that. Then size up if you're using soy, a heavy fragrance load, or dark dye, since those burn cooler. Confirm with a test burn that reaches the edges.

What happens if a candle wick is too small?

A wick that's too small can't melt wax all the way to the edge, so the candle tunnels a narrow shaft down the middle and wastes the outer wax. The flame stays weak and can drown in its own melt pool. The fix is to size up one wick, and to always give the first burn enough time to form a full edge-to-edge pool.

What happens if a candle wick is too big?

A wick that's too big burns with a tall, flickering flame that produces soot and a black mushroom tip, and it can overheat the container. The candle burns through too fast and can smoke. Size down one wick, trim it to 5 to 6 mm before each burn, and the flame should settle to a calm 2 to 3 cm.

Do soy candles need a bigger wick than paraffin?

Yes, usually one size bigger. Soy wax burns cooler than paraffin, so it needs more heat to melt cleanly to the edges and avoid tunnelling. Heavy fragrance loads and dark dyes push the same way. When switching a recipe from paraffin to soy, size the wick up and test-burn to confirm a full melt pool.

Are wooden wicks better than cotton?

Neither is better; they're different. Cotton wicks are reliable, easy to size, and suit most candles. Wooden wicks give a wider flame and a soft crackle that many people love, and they suit wider vessels, but they're more finicky to light and size. For a first candle, cotton is the easier choice; wooden wicks are a lovely upgrade later.

Wick sorted? Pour into a shape that shows it off — browse sculptural, easy-release designs in our candle mold collection.