Question 1

How much does quilting cotton shrink when washed?

Accepted Answer

Good-quality 100% quilting cotton typically shrinks about 2–3% in each direction when washed, though some fabrics shrink up to 5%. Cotton-polyester blends shrink less, usually 1–2%, because the polyester fibers are dimensionally stable. The exact amount varies by fabric, manufacturer, and washing method, so the percentage here is user-entered — measure your own fabric for the most accurate result.

Question 2

Is this fabric shrinkage or quilt shrinkage?

Accepted Answer

This tool is a QUILT shrinkage estimator — it takes the finished (as-sewn) quilt dimensions and returns the post-wash quilt size. It is not a raw-yardage calculator, though the reverse result shown works the same way for fabric: to end up with a given length after prewashing, buy required length ÷ (1 − shrinkage rate). Crosswise and lengthwise percentages are entered separately, because woven cotton usually shrinks more in one direction than the other.

Question 3

How is the post-wash size calculated?

Accepted Answer

Shrinkage is a percentage of the ORIGINAL (pre-wash) dimension. The amount lost in a direction is original × (shrinkage% ÷ 100), and the final size is original minus that loss — equivalently, final = original × (1 − shrinkage% ÷ 100). For example, a 50″ width at 2% shrink loses 1″ and finishes at 49″. You may enter a separate length percentage if your fabric shrinks more in one direction than the other.

Question 4

Should I pre-wash my fabric?

Accepted Answer

Pre-washing lets you cut and piece at the post-shrink size, so the finished quilt keeps its dimensions after its first wash and different fabrics do not shrink unevenly against each other. Not pre-washing produces a classic "vintage" puckered texture after the first wash, but the final dimensions are less predictable. Pre-washing also removes sizing and excess dye. The choice is a personal preference — this calculator shows you the post-wash size either way.

Question 5

Why does washing method matter?

Accepted Answer

Hotter water and heavier agitation cause more shrinkage (and can felt wool). Gentle / cold washing minimizes shrinkage; hot / heavy washing maximizes it. The washing method here is context only — it does not change the math. Enter the percentage that matches how you plan to wash the finished quilt.

Quilt Shrinkage Calculator — Post-Wash Quilt Size Estimator

What this calculator determines

Related calculators

Examples

50″ × 65″ quilt, 2% shrink → 49″ × 63.7″

50″ × 65″ quilt, 3% shrink → 48.5″ × 63.05″

Assumptions & Conventions

Frequently asked questions