Ceramic Glaze Ratio Calculator

What this ceramic glaze ratio calculator does

This calculator converts a glaze recipe written in parts (silica, alumina, and flux) into exact gram amounts for any batch size. You type in your total glaze weight plus the parts for each component, and the tool scales the recipe so you can weigh out your powders accurately.

It is designed for potters who work with simple three-part glaze systems and want to mix consistent test batches or production runs without doing ratio math every time.

Understanding silica, alumina, and flux in glazes

Ceramic glazes are usually described in terms of three functional roles:

• Silica (SiO₂) — the primary glass former that creates the transparent, glassy phase of the glaze.
• Alumina (Al₂O₃) — a stabilizer that stiffens the melt, improves durability, and helps prevent runs.
• Flux — materials (such as feldspar, whiting, frits, or alkali carbonates) that lower the melting temperature so the glaze matures at your firing cone.

In a simplified view, many base glazes can be thought of as a balance between these three roles. While real recipes break these roles across several raw materials, thinking in silica–alumina–flux ratios is a useful way to compare and scale formulas.

Glaze ratio formula (how the calculator works)

Glaze recipes in parts can always be scaled using a simple proportional formula. For each ingredient, the mass in grams is:

Where:

• M = mass of the ingredient (grams)
• P = parts for that ingredient
• S = sum of all parts in the recipe (silica + alumina + flux)
• T = total glaze batch weight (grams)

The calculator computes the sum of parts, then applies this formula to silica, alumina, and flux to give you gram amounts. You can verify the result by adding the three masses and confirming they are very close to your chosen total weight (minor rounding differences can occur).

Typical ratio ranges for silica, alumina, and flux

Every glaze has its own chemistry, but many cone 6–10 base glazes fall roughly into these parts ranges:

Use these as very rough starting points, not hard rules. The actual behavior of a glaze depends on which specific materials supply silica, alumina, and flux, plus firing temperature, atmosphere, and the clay body.

How to use the ceramic glaze ratio calculator

1. Choose your batch size. Decide how much dry glaze you want to mix. For test tiles, many potters use 100–200 g; for production, 1–5 kg is common.
2. Enter the total glaze weight. Type this value in grams in the Total Glaze Weight field.
3. Enter your parts. In the silica, alumina, and flux fields, enter the recipe in parts (not grams). For example, a simple base might be 70 silica, 20 alumina, 10 flux.
4. Run the calculation. Click the calculate button. The tool sums the parts and returns the required grams of silica, alumina, and flux for your chosen batch size.
5. Weigh and mix. Use a digital scale to weigh each component, combine them thoroughly, add water to your preferred consistency, then sieve to remove lumps.

Near the calculator output, you should see a clear breakdown showing how many grams of each component you need. You can copy this into your notebook or glaze log for consistent remixes later.

Worked example: scaling a test batch

Imagine you want to test a new transparent base glaze and you decide on a 500 g dry batch. Your target ratio is:

• Silica: 70 parts
• Alumina: 20 parts
• Flux: 10 parts

The sum of parts is:

S = 70 + 20 + 10 = 100 parts

Now apply the formula for each component.

Silica mass

M = (70 / 100) × 500 = 350 g

Alumina mass

M = (20 / 100) × 500 = 100 g

Flux mass

M = (10 / 100) × 500 = 50 g

Check: 350 + 100 + 50 = 500 g total, which matches the batch size you selected. You would then choose actual materials (for example, a feldspar mix for flux, kaolin for alumina, and silica sand or flint for silica), calculate how each one contributes to the three roles, and weigh them out.

The calculator performs this proportional scaling instantly, so you can focus on choosing materials, applying the glaze, and evaluating fired results.

Using results in your studio workflow

Once you have gram amounts from the calculator, a typical workflow might look like:

• Weigh each dry ingredient carefully on a stable digital scale.
• Dry-mix or blend the powders thoroughly to avoid local pockets of flux or silica.
• Add water gradually until you reach a brushing, dipping, or spraying consistency.
• Sieve the slurry through an appropriate mesh (commonly 80–120) for an even glaze layer.
• Apply to test tiles or sample pieces and fire to your normal kiln schedule.
• Record cone, atmosphere (oxidation/reduction), clay body, and visual results so you can refine the ratio later.

Interpreting and adjusting your glaze ratios

The silica–alumina–flux balance is one of several levers you can use to tune a glaze. After firing tests, you might adjust ratios based on what you see:

• Runs heavily or pools at the foot — consider reducing flux parts or slightly increasing alumina parts.
• Under-melted, dry, or rough surface — consider slightly increasing flux or silica, or firing a little hotter.
• Too glossy and sharp reflections — nudging alumina up can move you toward satin or matte surfaces.

Each time you update your parts, you can reuse the calculator to generate new gram amounts for the same batch size, or scale up to a production batch once you are happy with the test results.

Assumptions and limitations

This calculator focuses on ratio scaling and makes several important assumptions:

• Three-role simplification. It treats your glaze as a combination of silica, alumina, and a combined flux fraction. Real recipes often include additional roles (e.g., boron, opacifiers), which are not modeled here.
• No prediction of fit or food safety. The tool does not evaluate crazing, shivering, leaching, or suitability for food-contact surfaces. It only converts parts to grams.
• No material-specific behavior. It does not distinguish between different flux sources (e.g., feldspar vs. frit), clay bodies, or firing ranges. The same ratio can behave differently at cone 6 and cone 10, or on porcelain versus stoneware.
• Mathematical accuracy only. If your initial ratio is unbalanced, the calculator will still scale it perfectly; it cannot tell you whether a recipe is good, durable, or safe.

Always verify glazes through proper testing, especially before using them on functional ware.

Safety notes and responsible use

Many glaze materials can be hazardous, especially in dry, powdered form. Consider the following practices when using results from this calculator:

• Wear a suitable dust mask or respirator and eye protection when handling dry materials, particularly silica and any toxic colorants.
• Mix glazes in a well-ventilated area and clean up with a damp sponge rather than sweeping dust into the air.
• Research each raw material (for example, barium, lead, manganese, or copper compounds) and follow relevant safety guidelines.
• Perform leach testing and long-term use testing before treating a glaze as food-safe.

The calculator is provided as a convenience for scaling recipes. You are responsible for material handling, safety practices, and evaluating the performance and suitability of any glaze you mix.