# Clay Shrinkage Calculator

URL: https://speedycalculator.com/calculators/everyday-life/clay-shrinkage/
Last updated: 2026-10-25

> The clay shrinkage calculator works out how much a pottery piece shrinks from wet clay to fired size for a given shrinkage percentage, or how big to make a piece so it fires to the size you want.

## Inputs

- I know the
- Length / diameter (cm, in, mm, m)
- Width (cm, in, mm, m)
- Height (cm, in, mm, m)
- Total shrinkage (%)

## Results

- Length
- Width
- Height
- Volume change

## Formula

```
Fired size = wet size × (1 − shrinkage)
Wet size needed = fired size ÷ (1 − shrinkage)
Shrinkage % = (wet length − fired length) ÷ wet length × 100
```

## Explanation

Clay loses water as it dries and shrinks again as it is fired. Total shrinkage is typically 10–15% for stoneware and porcelain and 5–10% for earthenware. Measure your own clay with a test bar: draw a 10 cm line on wet clay and measure it after firing.

### How to use the Clay Shrinkage Calculator

- **I know the**
- **Length / diameter**
- **Width**
- **Height**
- **Total shrinkage**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Choose whether you know the wet size or the target fired size, enter the dimensions and the clay's total shrinkage.

### Tips

- Results are estimates meant for planning and fun – adjust the inputs to match your situation.
- Everything runs in your browser, so you can try as many variations as you like.
- Share the result link with friends so everyone sees the same numbers.
- For safety-related hobbies (hammocks, balloons, tents), follow the manufacturer's limits.

### Common mistakes to avoid

- Using default values when you know your own figures.
- Treating rough rules of thumb as exact.
- Forgetting to add breaks, travel or setup time.

### Inputs explained

FieldWhat to enterI know theChoose one: Wet (greenware) size, Fired size I wantLength / diameterUnits: cm, in, mm, mWidthUnits: cm, in, mm, mHeightUnits: cm, in, mm, mTotal shrinkageIn %

### Example values

How the main result changes when **Length / diameter** changes and everything else stays at the example values above:

Length / diameter (cm)Length (cm)7.56.611.259.91513.218.7516.522.519.83026.4

## Worked example

Inputs — I know the: Wet (greenware) size; Length / diameter: 15 cm; Width: 10 cm; Height: 12 cm; Total shrinkage: 12 %.

Results — **Length = 13.2 cm**; Width = 8.8 cm; Height = 10.56 cm; Volume change = -31.9 %.

## FAQ

**How much does clay shrink?**
About 10–15% for most stoneware and porcelain from wet to fired, less for earthenware.

**How do I measure clay shrinkage?**
Make a test bar, mark 10 cm while wet, fire it and measure: 8.8 cm means 12% shrinkage.

**Why does volume shrink more than length?**
Shrinkage happens in all three dimensions, so 12% in length means about 32% less volume.

**What formula does the Clay Shrinkage Calculator use?**
Fired size = wet size × (1 − shrinkage).