Clay Shrinkage Calculator
Calculate final dimensions after clay drying and firing for pottery and metal clay projects
Calculate Clay Shrinkage
Typical shrinkage ranges for different clay types
Typical range: 8-30% depending on clay type
Clay Shrinkage Results
Shrinkage Formula: Final dimension = Original dimension × (1 - shrinkage% / 100)
Shrinkage Factor: 0.9 (multiply original by this)
Volume Reduction: 0% decrease
Shrinkage Analysis
Example Calculation
Ceramic Bowl Project
Original dimensions: 15 × 15 × 8 cm
Clay type: Regular pottery clay
Shrinkage rate: 15%
Shrinkage factor: 1 - (15/100) = 0.85
Final Calculation
Final length = 15 × 0.85 = 12.75 cm
Final width = 15 × 0.85 = 12.75 cm
Final height = 8 × 0.85 = 6.8 cm
Final dimensions: 12.75 × 12.75 × 6.8 cm
Clay Shrinkage Rates
Regular Clay
10-20% shrinkage
Standard pottery clay
Air Dry Clay
8-12% shrinkage
No firing required
Silver Clay
8-30% shrinkage
Premium metal clay
Bronze Clay
8-30% shrinkage
Jewelry making
Copper Clay
9-25% shrinkage
Affordable metal clay
Clay Working Tips
Always account for shrinkage when planning project dimensions
Test fire small pieces to verify shrinkage rates
Add grog to reduce clay shrinkage
Metal clays shrink more than regular pottery clay
Understanding Clay Shrinkage
What is Clay Shrinkage?
Clay shrinkage is the reduction in size that occurs when clay dries and fires. During drying, water evaporates from the clay body, causing the particles to move closer together and the overall piece to become smaller.
Why Does Clay Shrink?
- •Water evaporation during drying reduces volume
- •Clay particles pack more tightly together
- •Chemical changes occur during firing
- •Organic binders burn away in metal clays
Shrinkage Formula
Final Dimension = Original × (1 - Shrinkage% ÷ 100)
- Final Dimension: Size after drying/firing
- Original: Size of wet clay piece
- Shrinkage%: Clay-specific shrinkage rate
Tip: Always make your original piece larger to compensate for shrinkage