Clay Shrinkage Reference Chart
Typical total shrinkage (wet clay to fired ware) by clay body type.
| Clay type | Total shrinkage | Confidence |
|---|---|---|
| Earthenware | 5–8% | typical |
| Stoneware (mid-fire, e.g. cone 5–6) | 10–13% | typical Heavily grogged or sculpture-grade stoneware bodies often shrink less, closer to 8–11%. |
| Porcelain | 12–16% | approximate Porcelain bodies vary more between manufacturers than stoneware/earthenware — check your specific body's data sheet. |
Sourced from Digitalfire’s ceramics glossary plus corroborating published ranges — see the code comment in this project’slib/clay-shrinkage-reference.tsfor full citations. Always confirm with your own test tile for anything where the final size matters.
Frequently asked questions
- Are these exact numbers for my clay?
- No — treat them as a starting estimate for planning. Real shrinkage varies by manufacturer, specific clay body, and firing temperature. For anything where the final size matters, fire a test tile and use the shrinkage percentage calculator to get your exact number.
- Why is porcelain marked "approximate" instead of "typical"?
- Porcelain bodies vary more between manufacturers than stoneware or earthenware do, so published ranges disagree more for porcelain — the range shown is wider and less certain as a result.
- What's the difference between drying shrinkage and firing shrinkage?
- Drying shrinkage happens as water leaves the clay between wet and bone-dry; firing shrinkage happens separately as the clay vitrifies in the kiln. The ranges in this chart are the TOTAL of both stages, from wet to fired — don't add a separately-published drying or firing figure to them, since that would double-count.