By Team Quiltdom
Use this free quilt sashing calculator to plan the strips between your quilt blocks. Enter your block size, how many blocks you have and how wide you want the sashing, and it gives you a complete cutting list: how many strips to cut, the exact size of every sashing piece and cornerstone, the yardage for each fabric, and your finished quilt top size.
It works with square or rectangular blocks, with or without cornerstones, and with or without sashing around the outside edge.
Quilt Sashing Calculator
All measurements in inchesNext step: add borders or work out the backing and batting for this quilt.
Cut sizes include 1/4 inch seam allowances on every side. Sashing pieces and cornerstones are cut from strips across the fabric width, then subcut. Without cornerstones, long strips are cut from strips joined end to end with straight seams. Each fabric includes 1 extra inch for straightening the edge, then rounds up to the nearest 1/8 yard.
How To Use The Quilt Sashing Calculator
- Enter your finished block size. Use the size the block will be once it is sewn into the quilt, without seam allowances. A block that measures 12 1/2 inches before sewing is a 12 inch finished block.
- Enter how many blocks across and down. Not sure yet? Our quilt size calculator works out the block count for your bed.
- Choose the sashing width and style. Pick whether you want cornerstones and whether the sashing should also run around the outside of the quilt.
- Read your cutting list. You get the strips to cut, the size of every piece, how many pieces come from each strip, and the yardage for the sashing and the cornerstones.
How To Calculate Quilt Sashing By Hand
Here is the math behind the calculator, using 20 blocks that finish at 12 inches, set 4 across and 5 down, with 2 inch sashing and cornerstones.
- Find the cut size of each sashing piece. Add 1/2 inch to both measurements: 2 1/2 x 12 1/2 inches.
- Count the pieces. Each row of 4 blocks needs 3 sashing pieces between the blocks, so 5 rows need 15. Each of the 4 rows of sashing between block rows needs 4 pieces, so that's 16 more. You need 31 pieces in all.
- Count the strips. Three 12 1/2 inch pieces fit in a 42 inch strip, so 31 pieces need 11 strips cut 2 1/2 inches wide.
- Convert to yards. Eleven strips at 2 1/2 inches is 27 1/2 inches, plus 1 inch to straighten the fabric. That's 28 1/2 inches, so buy 7/8 yard.
- Add the cornerstones. There is one wherever sashing crosses: 3 x 4 = 12 squares cut 2 1/2 inches. They all fit in one strip, so 1/8 yard is enough.
The finished size: width = blocks across x block width + (blocks across - 1) x sashing width. For this quilt, 4 x 12 + 3 x 2 = 54 inches wide and 5 x 12 + 4 x 2 = 68 inches long. If you add sashing around the outside, add twice the sashing width to each measurement.
How Much Fabric For Quilt Sashing? (Chart)
This chart uses 12 inch finished blocks with 2 inch sashing and cornerstones, sashing between the blocks only, cut from 42 inch quilting cotton. Use the calculator above for your exact numbers.
| Layout | Finished quilt top | Sashing | Cornerstones |
|---|---|---|---|
| 3 x 4 (12 blocks) | 40 x 54 in | 1/2 yd | 1/8 yd |
| 4 x 5 (20 blocks) | 54 x 68 in | 7/8 yd | 1/8 yd |
| 5 x 6 (30 blocks) | 68 x 82 in | 1 1/4 yd | 1/4 yd |
| 6 x 7 (42 blocks) | 82 x 96 in | 1 3/4 yd | 1/4 yd |
| 7 x 7 (49 blocks) | 96 x 96 in | 2 yd | 1/4 yd |
Sashing With Or Without Cornerstones?
Cornerstones are small squares where the sashing strips cross. They make it easy to line up your blocks, because every piece of sashing is the same length as a block, and a contrasting cornerstone adds a little extra sparkle.
Without cornerstones, you sew short sashing pieces between the blocks in each row, then join the rows with long strips. It's a calmer look and uses one fabric, but take care to line the blocks up across the long strips. Mark where each block should meet the long strip before you sew.
How Wide Should Quilt Sashing Be?
Most sashing finishes between 1 1/2 and 3 inches. A common rule of thumb is about one quarter of the block size, so 2 to 3 inches for 12 inch blocks and 1 1/2 inches for 6 inch blocks. Wider sashing makes the quilt bigger with fewer blocks. Try a few widths in the calculator to see how your finished size changes.
Quilt Sashing Calculator FAQ
How much fabric do I need for quilt sashing?
For 20 blocks that finish at 12 inches, set 4 x 5 with 2 inch sashing and cornerstones, you need 7/8 yard for the sashing and 1/8 yard for the cornerstones. More blocks, wider sashing and sashing around the outside all need more fabric.
How do you calculate the size of a quilt with sashing?
Multiply the number of blocks across by the finished block width, then add the sashing width once for every gap between blocks. Do the same for the length. Add twice the sashing width to both if the sashing also runs around the outside.
What size do I cut sashing strips?
Add 1/2 inch to the finished sashing width for the strip width, and 1/2 inch to the finished block size for the length. For 2 inch sashing between 12 inch blocks, cut each piece 2 1/2 x 12 1/2 inches.
Do cornerstones need a different fabric?
No, but a contrasting fabric is the usual choice because it frames each block. The calculator shows the cornerstone yardage separately so you can buy them in a different fabric if you like.
Is sashing the same as a border?
No. Sashing goes between the blocks, and borders go around the outside of the finished top. Use our quilt border calculator for the borders.
Plan The Whole Quilt
Work out your block count with the quilt size calculator, plan the sashing here, add borders with the quilt border calculator, then finish with the quilt backing calculator. All of our tools are on the quilting calculators page.