Sewing & Quilting Fabric Shrinkage Calculator
Created by: Lucas Grant
Last updated:
Estimate post-wash fabric dimensions and required pre-cut sizes so your final sewing and quilting pieces stay on target after prep.
Fabric Shrinkage Calculator
SewingEstimate post-wash size changes and pre-shrink cut dimensions
Fabric and Shrinkage Inputs
Target Finished Dimensions
Related Calculators
What is a Fabric Shrinkage Calculator?
A fabric shrinkage calculator estimates post-wash dimensions and required pre-shrink cut sizes from shrinkage percentages in width and length.
It helps prevent sizing errors in quilting and garment sewing by planning for real fabric behavior.
Fabric Shrinkage Formulas
Post-Wash Width: Original Width × (1 − Width Shrinkage%)
Post-Wash Length: Original Length × (1 − Length Shrinkage%)
Required Pre-Shrink Width: Target Finished Width ÷ (1 − Width Shrinkage%)
Required Pre-Shrink Length: Target Finished Length ÷ (1 − Length Shrinkage%)
Example Calculation
For 44 by 72 inch fabric with 4% width shrinkage and 5% length shrinkage:
- Post-wash width = 44 × 0.96 = 42.24 inches
- Post-wash length = 72 × 0.95 = 68.4 inches
- Use inverse formulas to calculate required pre-shrink cut sizes
Common Applications
- Garment sewing: Protect final fit after laundering
- Quilt prep: Keep block sizes consistent after wash
- Fabric purchasing: Add realistic shrinkage allowances
- Pattern adjustments: Plan cut dimensions for target finished size
Shrinkage Planning Tips
- Test shrinkage on a swatch from the same fabric lot
- Match wash and dry settings to final care routine
- Measure both width and length before and after prep
- Record shrinkage data for repeat fabric purchases
Frequently Asked Questions
What is fabric shrinkage?
Fabric shrinkage is the size reduction that occurs after washing, drying, or pressing, often expressed as a percentage.
Why should I calculate shrinkage before cutting?
Pre-calculating shrinkage helps you buy enough fabric and avoid undersized finished pieces after laundering.
How is shrinkage percentage calculated?
Shrinkage percent equals (original size minus washed size) divided by original size, multiplied by 100.
Do width and length shrink equally?
Not always. Many fabrics shrink differently in warp and weft directions, so width and length should be tracked separately.
Can pressing cause additional shrinkage?
Steam and heat can change dimensions further, especially in natural fibers. Test with the same prep process you will use in sewing.
What shrinkage margin is common?
Many sewists budget 3 to 8 percent for cotton fabrics, but actual values vary by weave and finishing treatment.
Should I still prewash after using this calculator?
Yes. The calculator supports planning, but prewashing or pre-shrinking is still recommended for reliable results.
Sources and References
- Textile care and dimensional stability testing references
- Sewing preparation guidelines for prewash and preshrink
- Fiber-specific shrinkage behavior studies and care labels