Glaze calculator and studio notebook
Free glaze chemistry for potters.
Understand your glazes, not just mix them. Enter a recipe and see its unity molecular formula (UMF), its silica to alumina ratio and its balance of fluxes at once. Keep your recipes, materials, colorants, notes and firing logs together in one private notebook.
No sign-up needed to try it · Free and open source · Your recipes stay private
See it work: a classic celadon base
| Material | Parts |
|---|---|
| Potash Feldspar | 40 |
| Silica | 30 |
| Whiting | 20 |
| Kaolin | 10 |
Its unity molecular formula
Fluxes - R₂O and RO
- K₂O : 0.264
- CaO : 0.736
Stabilizers - R₂O₃
- Al₂O₃ : 0.407
Glass Formers - RO₂
- SiO₂ : 3.710
Ratio of Silica to Alumina : 9.11
The fluxes add up to 1, so any two glazes can be compared fairly. Worked out right here in your browser by the same code the calculator uses.
What Glazecalc does
Instant unity formula
See fluxes, alumina and silica in unity, the way glaze chemists compare recipes, as soon as you enter a recipe.
Fix and substitute
A material discontinued? Compare formulas to find a replacement that melts the same way.
Your studio notebook
Keep recipes, your own materials, colorants, notes and firing logs together in one place.
Learn as you go
Plain-language guides, from what a glaze is to firing it safely, sit next to the numbers.
What is a unity molecular formula?
A glaze recipe says how much of each material to weigh out. The unity molecular formula, also called the Seger formula, says what those materials become in the kiln: how many molecules of each oxide there are, scaled so that the fluxes add up to one.
Fluxes make the glaze melt, alumina stiffens the melt, and silica forms the glass. Comparing those three groups explains why one glaze is glossy and another matte, or why one runs while another stays put, and it shows how to replace a material that is no longer sold.
Ready when you are.
Try the calculator now, then create an account to keep what you made.