Clay Shrinkage Calculator

Slab-Built Pottery Planner

I created this tool to solve a common pottery challenge: knowing exactly how big to make pieces before firing.

When I want to make a mug that's 3 1/2 inches tall after firing, I need to account for clay shrinkage. Previously, I'd manually calculate each measurement.

This calculator simplifies the process. Just enter your desired final dimensions and clay shrinkage percentage, and it will tell you the exact pre-firing measurements needed.

While I built this for my own studio work, I'm sharing it for anyone who wants consistent, predictable results in their pottery. Works in both inches and centimeters.

Looking for proven pottery designs? Download my personal collection of mug templates—the same ones I use in my studio for consistent, professional results. Perfect companion to this calculator!