I Want to Reduce the Number of Wick Sizes in My Business — Should I Choose Candle Jars With Similar Diameters Even If Their Capacities Differ?

Why height changes capacity but not (usually) the wick

Think about what the flame is doing. It melts a disc of wax, and a well-chosen wick melts that disc out to the glass in the first few hours of burning (3 to 4 hours is a common rule of thumb for the first burn). The disc's area depends on the inside diameter: π × r². Height is not in that formula. A jar twice as tall at the same inside diameter has the same disc to melt; it simply has twice as many centimetres of wax under it, so it burns for longer.

That is why a range built on one inside diameter can often share a wick across capacities. A 7 cm inside diameter gives a pool of about 38.5 cm², whether the jar holds 150 g or 300 g. Two jars of the same capacity but different diameters are the opposite case: same wax, different pool, usually different wicks, as the tall-narrow vs short-wide guide shows.

Why "usually" and not "always"

Height is not completely invisible to the wick. In a deeper jar, the flame spends more hours sitting further below the rim, the glass above the pool warms, and near the bottom the heat has more glass and less wax around it. A wick that is fine in an 8 cm jar can run a deeper pool or a hotter final third in a 10 cm jar. The test that settles it is a burn-down in the tallest jar of the band, not a first burn in the shortest.

The SKU maths: three diameters vs one band

Worked example: a maker launching three sizes, small (about 120 g), medium (150 to 200 g) and large (300 g or more). Range A picks the three sizes on looks, and they land on three different diameters. Range B picks three sizes that share one diameter band. The testing rules are our judgement: a nine-candle, three-rung bracket per diameter at launch; for range B, three confirmation candles in each other height; and for every new fragrance, two check candles per diameter (range A) or two in the band plus one burn-down in the tallest jar (range B). Each test candle is costed as a 150 g candle in a Clear 150 g jar with CSI 464, Jasmine and a C2 wick: ₹220.94, excluding labour, freight, packaging and GST.

The money in the table is modest: ₹2,651.25 at launch and ₹662.81 per fragrance. The larger saving is time. Every bracket is a cure plus several burn sessions, weeks of bench time you cannot spend making stock; a range that launches on one bracket reaches the market sooner and adds fragrances faster. And every extra wick-to-jar pairing is a chance for a production error that only shows up in a customer's candle.

What it does not save: the wick bill

Eco C1 is ₹5.90 a wick and C2 ₹9.44 a wick at every pack size from 10 to 1,000; Cotton Braided Wicks Ready Made is ₹12.00 a wick at every size from 10 to 1,000. Buying all your wicks as one size in larger packs does not lower the price per wick on any of them. It can even raise the bill, if the shared wick is a bigger rung than some jars would have needed:

The exception on our store is the Performance Wooden Wicks: ₹59.00 a wick in a pack of 10 and ₹41.30 in a pack of 100, 30% less per wick. A wooden-wick range that consolidates onto that listing does get a volume price. The listing does not offer widths as variants, so ask on WhatsApp which width you are buying before you design a band around it.

What one wick size does save is held stock. Three wick sizes usually means three open packs: three 100-packs of C1, C2 and Cotton Braided are ₹2,734.00 sitting on a shelf, against ₹944.00 for one 100-pack of C2. The per-wick price is the same; the cash tied up and the risk of a size running out mid-batch are not.

Building a band from CSI's range

Plotting every in-stock CSI jar that states a diameter (the diagram above) shows three columns. The 7 cm column is the deepest: 19 in-stock listings, from the 150 g apothecary jars through the 200 ml Matte family to the 300 g Green Iridescent jar. The 6 cm column has 8: seven Shiny 120 g colours (Black, Amber and Pink in packs of 1 or 5, the others singly) and the Shot Glass 130 g jar. The Apothecary Dome Lid jar stands alone at 10 cm, with 500 g (₹212.40) and 700 g (₹250.00) sizes described by one set of dimensions.

On paper the three are one band. In practice, a thick-walled 7 cm-outside jar and a thin-walled one can differ by several millimetres inside, and 5 mm on a 7 cm jar is about 15% of the pool (the 5 mm guide). The capacities do not scale cleanly with height either: 150 g and 200 ml at the same 8 cm height, 300 g at 10 cm. Those are signs of different glass, bases and capacity definitions, and the reason the first step is always a calliper and a scale. How close insides must be to share a wick is a technical question with its own guide, the one-wick tolerance guide; how to measure the inside is the external-versus-internal guide.

Where the one-band idea breaks

Very tall jars in the band. Adding capacity by height alone eventually gives a jar much taller than it is wide. Deep jars ask more of the last third: the flame sits low in a glass tube for hours. Our judgement: keep the band's tallest jar within a height you have proven with a burn-down, and treat anything taller as a new test, not a new SKU.

Wide luxury jars. At the wide end, one wick often stops being enough and the question becomes one, two or three wicks (the 1, 2 or 3 wicks guide). A wide band can still standardise, on a two-wick layout, but it is a different band.

Tapered or shouldered jars. A jar that narrows toward the base or has a shoulder has more than one relevant diameter. It can join a band only if its pool-height inside matches and its narrower bottom passes a burn-down.

Design variety. One diameter across a range can look repetitive on a shelf. Many brands vary finish, colour and lid instead of shape, which is where a family like the Matte, glossy and frosted jars helps: one inside, many looks, if the finishes burn the same in your tests.

Proving a band: the test plan

That is the fifteen-candle plan behind range B. Running a whole collection of fragrances through it is the standardisation programme in the 10 to 20 fragrance consistency guide; building the range around jars you can keep buying is the jar-continuity guide.

Jars and wicks for a 7 cm band

Three jars that put 150 g, 200 ml and 300 g on one stated 7 cm diameter, one 6 cm option for a gift size, and the wick you are likely to standardise on. Chosen on stated wording, price and stock on 26 September 2026; CSI publishes no burn data, so the band is yours to prove.

Frequently asked questions