Clay Shrinkage Calculator

Your details

Forward: enter your wet clay dimensions, get the expected fired size. Reverse: enter your desired finished dimensions, get the wet size you need to start with.
The percentage the clay shrinks from wet to fully fired. Most stoneware is 11-15%. Check your clay manufacturer spec sheet or fire a test tile.
%
How much the clay shrinks just from wet to bone dry, before firing. Typical range is 4-8%. The firing stage accounts for the rest.
%
The longest dimension of the piece.
cm
The second dimension. Leave at 0 to skip.
cm
The vertical dimension. Leave at 0 to skip.
cm
For bowls, lids, and cylinders. Calculated separately from length/width/height.
cm
Fired lengthTypical shrinkage
17.6cm

Length after full firing

Fired width13.2cm
Fired height8.8cm
Bone-dry length19cm
Total shrinkage12%
Shrinkage multiplier0.88
12% %
Low<8%Typical8%-15%High15%-20%Very high20%+

At 12.0% total shrinkage, your clay will lose 12.0% of its wet dimensions.

  • Every 10 cm of wet clay becomes 8.80 cm after firing at this shrinkage rate.
  • Drying accounts for 5.0% of shrinkage and firing accounts for 7.0%, so the piece will be noticeably smaller before it even enters the kiln.
  • Always fire a test tile with calipers to confirm your actual shrinkage rate, since kiln temperature and atmosphere affect the final result.

Next stepRecord your actual measured shrinkage from a fired test tile and update the rate above for a precise result.

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