Clay Shrinkage Calculator
Clay shrinks twice: once as it dries and again as it fires. If you throw to the finished size, every pot comes out undersized. This calculator works in the other direction — you specify the finished dimension and it tells you what to make.
Your dimensions
Enter the size you want the finished pot to be. The calculator works backwards to the wet size you need to throw.
Body presets
Presets are typical published figures. Every batch varies — run a shrink bar test on your own body before committing to a production run.
Notes and gotchas
- Total shrinkage is not the sum of drying and firing percentages — the second applies to the already-shrunk dry dimension.
- Measure your own body with a test bar rather than trusting a generic figure.
- Shrinkage compounds with size: a 1% error is 1 mm on a 10 cm pot and 5 mm on a 50 cm pot.
Estimates only. These calculators use standard ceramic relationships and typical material behaviour. Your clay body, kiln, elements and load will all shift the real numbers. Treat the output as a starting point, log what actually happens, and adjust.
Simulate it in 3D
Our studio simulators model the same relationships — throw a form, glaze it, cut a section or plot a firing curve.
Wheel Thrower
Shape a form and read off its capacity, height and the clay weight you will need.
Kiln Curve Simulator
Build a firing curve segment by segment and play it back as an animated schedule.
Glaze Painter
Paint glaze onto a rotating 3D pot and read the coverage and estimated glaze mass.