CandleEasy™
Join WaitlistJoin

Fill Weight Calculator

The water method — find any vessel’s true wax capacity.

Fill Weight

Your results will appear here

Weigh your vessel empty, then filled with water to the fill line.

Water Weight
—
Factor
0.842

Factor = density 0.90 × makers’ usual 0.935 — the number makers multiply the water weight by.

Enter your numbers first — then save the calculation or download it as a spreadsheet.

Step 1: Weigh your vessel

filled to your fill line

Step 2: Your wax

Average estimate — waxes in this category run 0.90–0.925; your product may differ, so use its published density if the sheet gives one.

Step 3: How full?

a little below your water line — room for cooling shrink and a lid. This is the 0.86 most soy makers use, derived: 0.921 × 0.935.

Wax is lighter than water, so the water weight is scaled down by your wax’s density and by how full you want the candle. The result is the finished candle — wax and fragrance together. Use it as the fill weight in the Fragrance Load Calculator for your first test pour.

How the math works — and where the numbers come from
How the math works
Weigh the empty vessel, fill it with water to where the top of the candle will be, and weigh again. The difference is the water weight.

Wax is lighter than water, so the calculator scales that weight by your wax’s density and by how full you pour:
finished candle weight = water weight × wax density × how full
250 g water × 0.90 soy × 0.935 makers’ usual = 210 g of candle
That’s wax and fragrance together. Use it as the fill weight in the Fragrance Load Calculator.
Your wax — three ways to get the density
A category average estimate. Averaged from the manufacturer data sheets we could document. Good for a first test pour.

Your wax’s published density. Find it on your wax’s Safety Data Sheet (SDS), section 9. Use the solid figure, not the liquid one (around 0.70).

Find out my own wax’s density. Use the small calculator above: pour wax to the same line as the water, then divide the wax weight by the water weight. It beats every average.
How full?
“Makers’ usual” leaves 6.5% of room for shrinkage and a lid. “Right at the line” uses the density alone.

The well-known “multiply by 0.86” isn’t a density. It’s soy’s 0.921 with that same 6.5% of room. That’s why it works for soy and under-fills beeswax.
Where these numbers come from
Each category is an average of the wax manufacturers’ own data sheets, reviewed September 2026:
Soy0.90avg of 0.90–0.925
Coconut & coconut blends0.87avg of 0.84–0.90
Coconut-apricot blend0.88avg of 0.86–0.90
Soy-coconut blend0.90avg of 0.84–0.925
Parasoy blend0.90avg of 0.87–0.925
Paraffin0.90avg of 0.87–0.92
Palm0.88avg of 0.85–0.90
Rapeseed / canola0.90avg of 0.90–0.91
Olive wax0.90avg of 0.88–0.92
Beeswax0.96avg of 0.95–0.98
Candle gel0.856avg of 0.854–0.858
Your wax’s own published density, or one measured pour, always beats an average. Coconut blends vary the most.
Weigh it once, pour it right — every jar after that is a water weigh away.

Ready to go beyond the numbers?

CandleEasy saves your formulas, walks your burn tests, tracks your supplies, sizes whole batches from your approved recipes automatically, and scans fragrance oils for blend compatibility before you buy.

Sign up