Clay & Shrinkage

Clay Weight Estimator

Estimate the correct amount of wet clay needed for a pot based on dimensions and form type.

Reviewed by ClayCalc Editorial · Updated

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Results

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Enter your measurements above and click Calculate.

Formula Explanation

Clay weight is estimated from the geometric volume of the form, the clay body's bulk density, and a form factor that accounts for hollow walls vs. a solid mass.

Volume = Form geometry × wall factor
Weight (g) = Volume (cm³) × density (g/cm³) × form_factor

Method & review note

About this calculation

Uses measured dimensions or weights and a stated arithmetic model. Clay and forming method vary, so production decisions should use test pieces from the actual body and firing.

Reference: Digitalfire — Drying Shrinkage. See the editorial methodology for testing, precision and corrections.

Input handling: Values are sent to the ClayCalc server for this request and are not written to the application database.

Read the Clay Shrinkage Test

Frequently Asked Questions

Why does the estimator use form factor coefficients? expand_more
Different forms use clay differently. A solid cylinder would weigh far more than a thrown cylindrical vase. Form factors (e.g., 0.25 for a bowl) are empirical averages derived from studio measurement across many potters.
What does "with waste" mean? expand_more
The "with waste" figure adds 12% to the estimated clay weight for trimming waste, centering clay that sticks to the wheel head, and general losses during forming.
Is the estimate accurate for hand-building? expand_more
For slab and coil building, use the slab form type for accuracy. Wall thickness has a large impact — measure your typical wall thickness and enter it carefully.