Maker Calculators
candles

Candle Wick Size Calculator

Find the right wick size for your candle. Enter your container diameter and wax type to get an instant wick recommendation.

10%
Dye used?

Recommended wicks

Primary recommendationECO-4Best starting point for pure soy in a 3" container
Alternative seriesCD-12Same size range, different series — test both
Testing noteAlways test 3+ wicks before committing to a production batch. Burn for 4 hours, check the melt pool reaches the container edges, and keep flame height between 1–1.5 inches.

How to choose the right candle wick size

Wick selection is the most tested and iterated part of candle making. Unlike wax amount or fragrance load, there is no perfect formula — every combination of container, wax, fragrance oil, and dye behaves slightly differently. This calculator gives you the best starting point based on established industry sizing charts, but wick testing is always the final answer.

What diameter measurement to use

Always measure the inside diameter of your container at the widest point of the wax pool — not the outside of the jar. For straight-sided containers like tumblers this is simple. For tapered containers like apothecary jars, measure at the widest interior point the wax will reach.

Why wax type changes wick size

Different waxes have different densities, melt points, and viscosities. Soy wax is softer and burns cooler, so it needs a slightly smaller wick than paraffin which burns hotter. Coconut wax sits between the two. Beeswax burns the hottest and uses a completely different wick series (square braid) because standard cotton core wicks struggle with its higher melt point.

How fragrance load affects wicking

Fragrance oil thickens the melt pool and can clog wick fibers over time. At loads above 10%, this effect becomes meaningful — the wick has to work harder to draw fuel. This is why heavy fragrance loads often require sizing up one step.

How to test candle wicks properly

  1. Make 3 test candles with the recommended wick, one size up, and one size down
  2. Let cure for 48 hours minimum (soy wax especially needs cure time)
  3. Burn for exactly 4 hours on the first burn
  4. Check: melt pool should reach the edges of the container, flame should be 1–1.5 inches tall, no black smoke, no mushrooming on the wick tip
  5. Extinguish, let cool completely, trim wick to ¼ inch, repeat for 3 more burns
  6. The wick that performs consistently across all burns is your wick

Frequently Asked Questions

Can I use the same wick for different fragrance oils in the same container?

Not always. Some fragrance oils are thicker (higher viscosity) than others and will behave more like a higher fragrance load. If you change fragrance oils, re-test even if the container and wax are identical.

What does mushrooming mean and is it bad?

Mushrooming is a carbon buildup on the wick tip that forms a small ball or "mushroom" shape. Some mushrooming is normal, especially with ECO wicks. Excessive mushrooming means the wick is too large — size down.

My candle tunnels and never reaches the edges — what does that mean?

Tunneling almost always means the wick is too small. Size up one step and re-test.

Does container color affect wick choice?

Dark glass absorbs more heat than clear glass, which can slightly affect burn behavior. It is rarely significant enough to change wick size but worth noting if you are between two sizes.

What is the difference between ECO and CD wick series?

Both are cotton core wicks suitable for soy and soft waxes. ECO wicks have a slightly different braid construction that produces a more self-trimming burn. CD wicks tend to produce a slightly brighter flame. Test both — many makers have a strong preference for one over the other.