For practice, try roughly 1–1½ pounds for a small mug body, 1½–2 pounds for a small bowl or 2–3 pounds for a modest plate. Adjust downward if you cannot center it comfortably. These are trial amounts; finished size depends on shape, thickness, trimming and shrinkage.
Begin with a manageable trial range
Weigh equal portions for a short trial and record what each becomes. The ranges above are suggested starting points, not manufacturer prescriptions or guaranteed dimensions.
Weigh handle clay separately from mug-body clay. For plates, record the intended diameter; comparing weights without the form’s dimensions says little about where the material went.
Record what stays and what comes off
Keep the body and firing schedule consistent while establishing your baseline, and identify both in the record.
- Starting clay weight, with handle clay counted separately.
- Thrown height and width.
- Trimmed weight if useful, plus notes on a heavy base or substantial trimming.
- Fired dimensions.
Account for shrinkage with the right figure
Lakeside Pottery describes shrinkage during both drying and firing. Use the figure for your body and firing condition, then verify it with your own pieces before making a fitted set.
As hypothetical dimension arithmetic, a piece that shrinks 10% in the measured direction would need to start at about 11.1 cm to finish at 10 cm: 10 divided by 0.90. Simply adding 10% gives a different result. This example does not predict the shrinkage of your clay, and it does not calculate the starting clay weight.
Change one variable for the next attempt
If the first cup is too heavy but the right size, improve the wall and base proportions before adding more clay. If it is well formed but too small, increase the next portion slightly and record the change. If you repeatedly leave much of a larger lump on the wheel, a smaller controlled portion may teach you more.
For a set, compare the first few pots before throwing the full batch. Keep a reference piece or dimension note beside the wheel.
Questions about this topic
Does the wheel’s centering capacity tell me how much clay to use?
No. It is a manufacturer rating for the machine, not a beginner portion recommendation. Start with an amount you can control.
Why do equal clay weights make different-sized pots?
Shape, wall thickness, leftover base material and trimming all change how much of the starting portion becomes the finished form.