Glaze Coverage Calculator (Glaze per Piece, Pieces per Bucket & Cost per Pot)

How it works

wet glaze volume = glazed area × wet thickness × coats · dry material (Brongniart, ρ = 2.6) = (wet weight − wet volume) × ρ ÷ (ρ − 1) · pieces per bucket = (bucket − working minimum) ÷ glaze per piece · mug area ≈ 2πdh + πr² (both wall faces + inside base)

Glaze goes onto a pot as a wet layer whose volume is simply the surface area times the thickness, most of it water that the bisque sucks in and then releases as it dries. Knowing that volume per piece tells you how many pots a bucket can glaze before it is too low to dip in, how much dry material to mix to replace it, and what the glaze on each pot actually costs — usually far less than potters guess. The calculator estimates surface area from the form and applies Brongniart's formula to split the wet glaze into dry material and water.

Worked example

A 9 cm × 10 cm mug glazed inside and out has about 629 cm² of glazed surface. One 1.2 mm dip at SG 1.45 uses about 75 mL (109 g) of glaze — roughly 55 g of dry material and 54 g of water — firing to about 0.4 mm of glass. A 10 L bucket holds about 7.3 kg of dry glaze; keeping 5 L as a working minimum, it glazes about 66 mugs before topping up, and the glaze on each costs about $0.33 at $6/kg dry.

Frequently asked questions