Clay Body Recipe Calculator

The calculator sums clay, feldspar, silica, and flux percentages, and if the total exceeds 100%, it computes a normalizer (100 divided by the total) and scales all four percentages down proportionally before calculating weights. This keeps the four ingredients from silently exceeding your batch size — the relative ratios between ingredients stay the same, only their absolute share shrinks.

Water isn't part of the percentage normalization at all — it's always estimated as 22% of the batch's total dry weight (the batch size you entered), independent of how the clay/feldspar/silica/flux percentages are split or whether they were normalized. That 22% figure is a typical addition rate cited for reaching workable throwing consistency, not a chemistry-based calculation.

Remainder is whatever's left of your batch size after weighing out the four named ingredients (clay, feldspar, silica, flux), floored at zero. It's only nonzero when your original four percentages sum to less than 100% — for example, if you entered 40/20/15/5 (80% total), the calculator still weighs out actual amounts for those four at their entered percentages, and the remaining 20% of the batch shows up as unaccounted-for material you'd need an additional ingredient or filler to fill.

It only handles the arithmetic of scaling percentages to weights for a given batch size — it has no model of clay chemistry, particle size, or firing behavior, so it can't tell you whether a given clay/feldspar/silica/flux split will produce a sound, well-fired body at your target cone. That depends on the specific materials you use (which kaolin, which feldspar) and your kiln's actual firing profile, which is why test-firing a small batch before committing a full one is essential.