Free local ceramics studio planner
Test the clay.
Plan the size.
Turn your own wet-to-fired test-bar measurement into a clear starting size for one ceramic piece. Keep the number tied to the clay body and firing you actually use.
1 · Calibrate from one test bar
2 · Name the finished size
A measured guide, not a firing promise
Divide by the fired factor — do not just add the percentage.
The planner first finds a fired-size factor: fired test length ÷ wet test length. The shrinkage percentage is 1 minus that factor. To work backward from a target, it divides the target by the fired-size factor. A 12% shrinkage rate has a 0.88 factor, so a 100 mm target starts at about 113.6 mm wet.
Make and measure the test bar with the same clay body, moisture state, forming direction, drying approach, glaze and final firing schedule you intend to use. Keep the card with that studio recipe instead of reusing it across clay bodies or firing changes.
This planner does not determine a clay body, firing temperature, glaze fit, absorption, warping, cracking, food safety, kiln schedule or final tolerance. It estimates linear dimensions from your own two measurements. See Digitalfire's shrinkage-test reference ↗