Size from the filled jar, lid on
Measure the jar at its widest point with the lid fitted, then add the allowance for the box. A shelf carton fits closely so the jar cannot rattle; the candle box uses a paperboard collar for that. A shipper is sized to the jar plus about three quarters of an inch so the cradle has room to hold it off the walls. Send the jar dimensions with your brief and the dieline comes back drawn to them.
Protect the glass, not just the box
Glass candles break at the corners and when the jar slides into a wall. The cradle in the candle shipper stops both. A retail carton on its own is a shelf box; if it is going into the mail, put it inside a shipper or a corrugated box with an insert. Our guide to shipping candles safely covers heat and cushioning for summer transit.
Finishes that suit wax and scent
Kraft with one color reads as small-batch and honest. White SBS with soft-touch and a gold or champagne foil scent name reads as a gift. Spot UV does not work on uncoated kraft, so use foil there instead. Keep a clear panel for burn instructions and warning text; the size of that panel is easier to plan on the dieline than after the art is finished.
Labeling notes
Candle warning and burn instructions are usually printed on the vessel label, the carton or both. Plan panel space for whatever text your compliance review calls for before the artwork is final.
This is packaging guidance, not legal advice.