Quilt Block Calculator
Plan a square or rectangular quilt block from its finished size and grid. Enter your own seam allowance, shrinkage, and pattern allowance so the estimate reflects your process.
A QUICK WALKTHROUGH
How to use this tool
- Enter finished width and height and grid columns and rows.
- Enter the seam allowance per edge, shrinkage percentage, and pattern allowance percentage.
- Review the finished unit, adjusted cut size, piece count, and net cut area.
Geometry and allowances
Finished unit = finished block dimension ÷ grid count. Base cut size = finished unit + 2 × seam allowance. Adjusted cut size = base cut × (1 + pattern allowance) ÷ (1 − shrinkage). Width and height are calculated independently.
No universal fabric claim
Shrinkage, cutting margin, layout waste, grain direction, and directional prints vary by project. This page reports the values implied by your inputs and does not recommend a universal percentage. Fabric area is net cut-piece area only.
GOOD TO KNOW
Common questions
What does pattern allowance mean here?
It is your extra percentage for the pattern or cutting plan, applied to the base cut size before shrinkage compensation.
Can I use metric units?
Yes. The calculator is unit-neutral; use the same unit for every dimension.
Does it include layout waste?
No. Add your own pattern allowance or interpret the net area with your cutting layout in mind.
Is this a sewing standard?
No. Use the seam, shrinkage, and allowance values appropriate to your materials and method.