Pottery Glaze Batch Calculator
Glaze recipes are written as parts that sum to a base, usually 100, and to mix a real batch you scale every material to your target dry weight. This calculator takes up to four materials with their recipe parts, scales them to the batch weight you want using the recipe total, and reports each material's weight in grams. It also computes the water to add as a percentage of the dry weight, which sets the glaze consistency. Water content and recipe parts are yours to enter, so the calculator works for any glaze, base-100 or otherwise.
Glaze scaling formula
Total parts = m1 + m2 + m3 + m4
Scale factor = batch weight / total parts
Material weight = parts * scale factor
Water = batch weight * (water% / 100)
Each material is scaled by the same factor so the proportions are preserved exactly. Water is computed from the dry batch weight; 1 mL of water weighs 1 gram, so grams and millilitres are interchangeable here.
Glaze mixing context
- Recipes are normally written so the base materials sum to 100 parts.
- Colourants and additives are quoted as parts per hundred on top of the base.
- Weigh each material accurately, since proportions drive melt and colour.
- Water percentage sets the application consistency; adjust to your target specific gravity.
- The gram and millilitre are SI-based units defined through the NIST weights and measures programme.
Glaze batch: frequently asked questions
How do I scale a glaze recipe to a batch?
Glaze recipes are written as parts that sum to about 100, the base. To scale to a batch, multiply each material's parts by the batch weight divided by the recipe total. A 500 gram batch of a recipe totalling 100 parts multiplies every part by 5. The calculator does this for each material you enter.
Why do glaze recipes total around 100?
Glaze base recipes are conventionally normalised so the main materials sum to 100 parts, which makes percentages and additions easy to read. Colourants and additives are then given as extra parts on top of the 100, expressed per hundred. Enter your recipe's actual total; the calculator handles totals other than 100.
How much water do I add?
Water is added to reach a workable specific gravity and is usually given as a percentage of the dry weight, often near 80 to 90 percent for dipping, but it varies by glaze and application. Because it is recipe and method specific, water is a user-editable percentage here. Adjust to your target consistency.
What is a base-100 recipe versus additions?
The base is the set of fluxes, glass formers, and stabilisers that sum to 100. Additions such as colouring oxides, opacifiers, or suspenders are quoted as parts per hundred on top of the base. This calculator scales whatever materials and parts you enter against the total you give, so it covers both.
Should I weigh dry materials precisely?
Yes. Glaze results depend on accurate proportions, so weigh each material on a scale to the gram or better. Mixing approximations changes melt behaviour and colour. The calculator gives each material's exact weight for your chosen batch size so you can weigh them out directly.
Official sources
- NIST: SI units (gram and millilitre).
- NIST: Office of Weights and Measures.
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.