Candle Wick Size Calculator

Why wick sizing matters:

The wick is the single most important variable in candle making. Too small and you get tunneling: the wax melts in a narrow channel around the wick while the outer ring stays solid, and it never recovers, because the first burn sets the width of every burn after it. Too large and you get soot, a tall flickering flame, and wax consumed far faster than it should be.

The golden rule: The melt pool should reach the full diameter of the container within 1–2 hours of the first burn. This is called a “full melt pool” and prevents tunneling on all subsequent burns.

Wick sizing depends on three things:

1. Container diameter: wider containers need larger wicks
2. Wax type: soy wax has a lower melt point and needs a hotter wick than paraffin
3. Fragrance and dye load: heavy loads can clog the wick, requiring a size up

General wick size chart (cotton core, flat braid):

Each bracket runs up to but not including its top figure, so a jar measuring exactly 3 inches takes the ECO-8 rather than the ECO-4. Our wooden wick calculator uses the same boundaries, so the two agree on where a jar sits.

Coconut wax behaves close enough to soy that it takes the same column. Beeswax sits with paraffin: it is dense and slow to melt, so it wants the hotter wick, and even then it is usually worth going up one size if the melt pool is lazy.

Worked example:

A 3-inch (76.2 mm) diameter jar with soy wax and 8% fragrance load:

• Start with ECO-8 or CD-8
• A heavy fragrance load can choke the wick, so ECO-10 is the sensible second test

Testing protocol: Always burn-test a new combination. Light the candle and check at 1 hour and 2 hours:

• Full melt pool in under 2 hours = correct wick
• Tunneling after 2 hours = wick too small, size up
• Flame taller than 1.5 inches or sooting = wick too large, size down

Double wicking: Containers wider than 4 inches benefit from two smaller wicks spaced evenly, rather than one oversized wick. This gives a more even melt pool and cleaner burn.