Wool Felting Calculator

Shrinkage prediction from wool type and agitation.

Wool type

Water temperature (°C)

Agitation level

Solution pH

Superwash treated

Tab to move between fields

Area shrinkage (%)

1.1

Linear shrinkage (%)0.6

Thickness increase (%)0.7

Final dimension (% of original)99.4

Reversibility score (0-100)80

Safe wash temp (°C)20

Felting risk (0-4)0

How to Use This Calculator

How the result changes with Water temperature (°C)

Wool type: 0=Merino (fine, high felting), 1=Corriedale (medium), 2=Lincoln/Leicester (coarse), 3=Alpaca, 4=Mohair.
Water temperature (°C): Wash water temperature. Felting accelerates sharply above 40°C.
Agitation level: 0=Soak only, 1=Gentle hand wash, 2=Machine gentle cycle, 3=Machine normal cycle.
Solution pH: pH of wash water/detergent. Alkaline (>8) opens wool scales and increases felting. Use pH 5-7 for wool.
Superwash treated: 0=Untreated wool, 1=Superwash (chlorine-Hercosett) treated to resist felting.

Area shrinkage (%): Predicted percentage reduction in fabric surface area from felting.
Linear shrinkage (%): Predicted percentage reduction in each dimension (length and width).
Thickness increase (%): Estimated increase in fabric thickness as fibers compact.
Final dimension (% of original): Each dimension will be this percentage of the original measurement.
Reversibility score (0-100): Likelihood that shrinkage can be reversed by stretching. Above 50 = possible, below 20 = likely permanent.
Safe wash temp (°C): Maximum recommended wash temperature for this wool type.
Felting risk (0-4): 0=Minimal, 1=Low, 2=Moderate, 3=High, 4=Severe.

Identify Input Parameters
4 parameters
Wool type = 0, Water temperature (°C) = 30, Agitation level = 1, Solution pH = 7 = 5 input(s) provided
Calculate Area shrinkage
Area shrinkage
1.1 = 1.1
Calculate Linear shrinkage
Linear shrinkage
0.6 = 0.6
Calculate Thickness increase
Thickness increase
0.7 = 0.7