How to Calculate Wool Shrinkage for Wet Felting

How do you calculate wool shrinkage for wet felting? Measure a test sample before felting and again after it has been felted and dried. Divide the lost length by the starting length. To estimate your layout size, divide the desired finished size by the proportion remaining.

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This guide covers measured shrinkage in wet felting. Do not apply its example percentage to a dry needle felted pet portrait or sculpture.

1. Measure your own sample

Prepare a small wool layout with the same wool, layer arrangement and thickness planned for your project. Record its starting length and width. Felt it using your intended process, let it dry, and measure again.

Record both directions separately. The numbers below are worked examples, not measured shrinkage rates for a particular wool brand or fiber type.

2. Calculate shrinkage and the enlargement factor

Shrinkage = (starting length − finished length) ÷ starting length. Multiply by 100 to express it as a percentage.

If a 20 cm sample finishes at 16 cm: (20 − 16) ÷ 20 = 0.20, or 20% shrinkage. The remaining proportion is 0.80.

Estimated starting size = desired finished size ÷ remaining proportion.

For a desired finished length of 25 cm with this sample result: 25 ÷ 0.80 = 31.25 cm. The enlargement factor is 1.25.

3. Why adding 20% is not the same as allowing for 20% shrinkage

Adding 20% to 25 cm gives 30 cm. If that shrinks by 20%, it finishes at 24 cm, not 25 cm. Dividing by 0.80 gives the appropriate starting estimate for this example.

4. Calculate length and width separately

If your sample starts at 20 × 20 cm and finishes at 16 × 18 cm, the length retains 80% and the width retains 90%. For a target of 25 × 15 cm, estimate the starting layout as 25 ÷ 0.80 by 15 ÷ 0.90: approximately 31.25 × 16.67 cm.

Keep the sample orientation recorded so you use the correct measurement for each direction.

5. Keep a sample record

• Wool type and batch.
• Starting dimensions, layer arrangement and thickness.
• Felting process and intended finish.
• Dry finished dimensions in both directions.
• Calculated shrinkage and enlargement factor.

Use the calculation as a starting estimate and check the project as you work. A test sample does not guarantee a particular finished tolerance, especially when the project differs in shape, thickness or construction.

Common questions

What shrinkage percentage should I use for Merino wool?

Use the result from a sample made for your project. This guide does not assign one percentage to all Merino wool.

Does 20% length shrinkage mean 20% area shrinkage?

No. If both dimensions retain 80%, the area retains 0.80 × 0.80 = 64%, which means a 36% area reduction.

Does this formula apply to dry needle felting?

This example is for wet-felting layout calculations. For a dry needle felted sculpture, see our guides to core wool and finishing wool and needle felting firmness.

Choosing the size of a finished keepsake

Wet-felting shrinkage calculations and the listed dimensions of a finished needle-felted sculpture serve different purposes. If you are buying art, check the measurements and included pieces on the product page instead of applying the sample shrinkage rate above.

Explore handmade wool figurines and scenes, or see the size and pet-count options for our custom pet portrait frame. Contact elsa@ilovefelt.com before ordering if a particular display space or gift date matters.

Explore finished artwork from our studio

Fox with Mushroom Basket | Handmade Needle Felted Wool Art

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Needle Felted Mouse Figurine — Handmade Wool Sculpture, Whimsical Storybook Home Decor

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Choose your preferred size or design on the product page and review what is included. For a gift deadline or a custom idea, ask us before ordering.

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