Fabric Shrinkage Calculator
Calculates how many extra yards of fabric to purchase to account for shrinkage when pre-washing before sewing. Essential when working with natural fibers like cotton or linen that shrink significantly.
About this calculator
Fabrics shrink when washed and dried due to fiber relaxation and heat. This calculator estimates the total shrinkage factor by summing three percentage-based variables — fabric type, wash temperature, and dryer heat setting — then adds them to 1 to form a multiplier. The formula is: Fabric to Buy = ⌈(requiredFabric × (1 + fabricType + washTemperature + dryerHeat)) × 8⌉ / 8. Each variable (fabricType, washTemperature, dryerHeat) is expressed as a decimal shrinkage rate (e.g., 0.05 for 5%). Multiplying by 8 before ceiling-rounding, then dividing by 8, snaps the result to the nearest one-eighth yard — matching the fractions fabric stores actually cut. This ensures you always have enough pre-washed fabric to meet your project's requirements.
How to use
Say your project needs 3 yards of cotton quilting fabric. Cotton has a shrinkage factor of 0.05 (5%), you plan to wash in hot water adding 0.04 (4%), and use a high-heat dryer adding 0.03 (3%). Step 1: Sum shrinkage factors — 0.05 + 0.04 + 0.03 = 0.12. Step 2: Build the multiplier — 1 + 0.12 = 1.12. Step 3: Multiply — 3 × 1.12 = 3.36 yards. Step 4: Round up to nearest ⅛ yard — ⌈3.36 × 8⌉ / 8 = ⌈26.88⌉ / 8 = 27 / 8 = 3.375 yards. Buy 3⅜ yards.
Frequently asked questions
How much does cotton fabric typically shrink when washed?
Cotton typically shrinks between 3% and 7% depending on the weave and finish. Tightly woven quilting cotton tends toward the lower end, while loosely woven or unfinished cotton can shrink 7% or more. Washing in hot water and drying on high heat compounds the effect. Pre-washing before cutting is strongly recommended for cotton garments and quilts to avoid distortion after the finished item is laundered.
Why is fabric shrinkage calculated to the nearest one-eighth yard?
Fabric stores and online retailers cut and sell fabric in increments of one-eighth yard (4.5 inches) because bolts are measured on rulers divided into eighths. Rounding your shrinkage calculation to the nearest ⅛ yard ensures you order an amount the store can actually cut for you. Ceiling-rounding (always rounding up) means you never end up short of pre-washed fabric for your project.
Does dryer heat cause more shrinkage than washing temperature?
Both factors contribute to shrinkage, but dryer heat — especially sustained high heat — is generally the larger driver for most natural fibers. Washing agitation loosens fiber tension, but it's the heat of drying that causes fibers to contract and set in their shrunken state. Using a low-heat or air-dry setting can significantly reduce total shrinkage, sometimes cutting it by half compared to high-heat drying. If you always air-dry finished garments, you may be able to use a lower shrinkage estimate.