Fabric Shrinkage Calculator
Cutting Bigger Than the Finished Size, on Purpose
Most woven and knit fabrics shrink somewhat after their first wash, which means cutting a garment piece to its exact finished dimensions guarantees an undersized result once it's laundered. Pattern makers solve this in two directions: measuring shrinkage from a test wash, and then working that percentage backward to determine how much larger to cut in the first place.
The Formulas
Shrinkage% = ((Original Length − Washed Length) ÷ Original Length) × 100
Cutting Length = Desired Final Length ÷ (1 − Shrinkage% ÷ 100)
Cutting Length = Desired Final Length ÷ (1 − Shrinkage% ÷ 100)
The second formula is the first one solved in reverse: given a known shrinkage rate and a target finished measurement, it returns the larger length that needs to be cut so the piece shrinks down to the correct final size.
Where This Matters
- Pattern grading — shrinkage compensation is applied before cutting so finished garments land on their intended size after the customer's first wash.
- Testing a new fabric lot — measuring shrinkage% on a swatch before a full production run catches fabrics that shrink more than the pattern was designed for.
- Quality specifications — buyers often set a maximum acceptable shrinkage percentage that incoming fabric must meet.
Worked Examples
| Mode | Inputs | Result |
|---|---|---|
| Calculate Shrinkage % | Original 100, washed to 97 | 3% shrinkage |
| Calculate Cutting Length | Desired 100, at 3% shrinkage | 103.09 (cutting length) |
How to Use This Calculator
- Choose a mode: Calculate Shrinkage % or Calculate Cutting Length.
- For Calculate Shrinkage %: enter Original Length and Washed Length.
- For Calculate Cutting Length: enter Desired Final Length and Shrinkage Percent.
- Select Calculate to get the result for the chosen mode.
Related Calculations
Apply the resulting cutting length to a full roll with the Fabric Yield Calculator, or check the fabric's weight with the Fabric Weight Calculator.