Clay Shrinkage During Drying and Firing | Preventing Defects
For a example, if clay shrinks 5% during drying, a piece of clay that is 5" long, will shrink 1/4" and a piece that is 20" long, will shrink 1" during the drying. This is why it is beneficial to know that the larger the piece is, the more important it becomes to let it dry evenly (slow drying will yield even drying).