Candle Melt Pool Timer

Melt pool depth grows downward from the top surface at a fairly constant rate once a pool forms, so the time to melt edge-to-edge is governed almost entirely by how far the wax has to travel sideways from the wick — the diameter — not by how much wax sits below it. A tall, narrow jar and a short, wide jar with the same diameter reach a full melt pool in roughly the same time even though their volumes differ substantially.

The calculator floors wick trim at 1/16 inch specifically to keep the trim factor from dividing by a near-zero number and producing an unrealistic result; trims that short are also a fire-safety problem since the flame can drown in its own wax pool. A trim longer than 1/2 inch typically means the flame is already mushrooming and sooting well before it reaches whatever melt pool time this tool projects, so re-trim before burning rather than trusting the estimate.

In this calculator, wax type only changes the hours-per-inch rate (1.2 for soy, 0.8 for paraffin, 1.0 for coconut) that gets multiplied by diameter — it doesn't otherwise alter the formula. In real burning, wax type also affects scent throw, how visible tunneling becomes, and how forgiving the wax is of an imperfect first burn, but those effects aren't modeled here.

The 4-hour figure this calculator compares against is a fixed safety ceiling, not a target to approach; a result of 3.5 or 3.8 hours means you're burning right up against the recommended maximum just to get a first full pool, which leaves little margin. In that situation, consider a shorter wick trim within the supported range or accept that the first burn may need to happen in two shorter sittings rather than pushing a single burn past 4 hours.