Quilt Size Calculator
Plan your quilt by entering block layout, sashing, borders, and seam allowances. The calculator outputs finished quilt size plus backing and batting requirements.
Finished quilt size
71.5" wide x 93.5" tall
Total blocks: 48
Backing and batting
Backing: 79.5" x 101.5"
Yardage: 6.23 yd
Quilt top summary
Top area: 6685 square inches
Sashing strips: 82
How to Use This Calculator
Plan the block layout
Enter how many blocks you want across and down plus the finished size of each block.
Add sashing and borders
Include optional sashing width and border size to see how they change the quilt dimensions.
Check finishing requirements
Use the calculated backing and batting sizes when shopping or piecing fabrics.
Formula
Finished width = Blocks across x Block size + (Blocks across - 1) x Sashing + 2 x Border + 2 x Seam allowance
Finished height = Blocks down x Block size + (Blocks down - 1) x Sashing + 2 x Border + 2 x Seam allowance
Backing size = Finished size + 2 x Overhang
Backing yardage = (Backing width x Backing height) / 1296
Example: 6 by 8 blocks at 10 inches with 1 inch sashing, 3 inch borders, and 4 inch overhang yields a quilt about 70 by 94 inches and backing of 78 by 102 inches (~1.74 yards).
Full Description
This calculator helps quilters translate design ideas into precise measurements. Tweak block counts, add sashing, or adjust borders to achieve the desired finished size without manual math.
Backing and batting requirements update automatically, so you know how much extra fabric to purchase beyond the quilt top. Customize the backing overhang to match longarm quilting preferences or your own finishing style.
Use the calculator when planning guild projects, selecting fabric yardage at the quilt shop, or teaching new quilters how layout choices affect finished size.
Frequently Asked Questions
How do I handle multiple borders?
Add the widths of all border layers together before entering the total. Alternatively, run the calculator for each layer and sum the changes.
Can I use this for on-point layouts?
The calculator assumes straight-set blocks. For on-point quilts, convert block dimensions to their diagonal size before entering them.
Does the backing size consider fabric bolt width?
No. Compare the backing width to your fabric width to see if you need to piece multiple panels.
How much extra backing should I add?
Four inches on each side is a common allowance for longarm quilting. Adjust the overhang field to match your quilter’s request.
Where do I calculate binding?
Use a dedicated quilt binding calculator to compute strip counts and binding length after you know the finished perimeter.