Plan two-at-a-time HSTs, or switch to a separate two-stage hourglass recipe.
Your measurements
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Your cutting plan
Ready when you are
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Measure your fabric. We'll work out the plan.
Measure your fabric. We'll work out the plan.
Enter your dimensions, then select Calculate. Or use the example to see a plan take shape.
Sew a test pair first. Trim each unit to the unfinished size before joining it into the quilt.
Convert a known length
A measurement reference, separate from your cutting plan. It converts length only; fabric width is not needed.
Make a test pair before cutting the batch
Cut matching starting squares from fabrics A and B. This plan uses finished size + 7/8 inch + your trimming extra. Place one of each right sides together. Mark a diagonal, sew 1/4 inch on both sides, then cut along the marked diagonal. Press the two units open. Trim each to finished size + 1/2 inch; the final seams bring it to the finished size. Worked example below: 17 HSTs finishing at 4 1/2 in. Use your cutting plan above for your own dimensions.
Cut on the marked diagonal, between the stitches
Oversized starting pair: one 5 1/2 in square from each fabric.
Stitch 1/4 in on each side of the marked diagonal. Cut on the diagonal itself.
Aligned starting squares
5 1/2 x 5 1/2 in starting cuts; right sides together.
Starting cut edge / diagonal cutting line
Stitching, 1/4 in from the cutting line
The square outlines represent two aligned layers. The solid diagonal is the cut, not either dashed stitching line. Quarter-inch seam distances are perpendicular to the diagonal. Sew a test pair before the batch.
Trim the sewn unit to five inches
Oversized starting square: 5 1/2 in.
Final unfinished trim target: 5 x 5 in.
Future finished contribution: 4 1/2 x 4 1/2 in, after surrounding 1/4 in seams.
Traditional starting alternative: 5 3/8 in; it does not give the same trimming room.
Preserve the corner-to-corner seam
Dotted inset: 1/4 in on each outside edge.
Final trim / raw edge
Sewn diagonal seam
Future finished boundary
This shows the final trimmed unit, not the starting square or the unknown pressed excess. Align the ruler's 45-degree line with the diagonal seam. A sewn unit must actually cover the full five-inch trim target; trimming cannot enlarge it.
For 17 units finishing at 4 1/2 in, the illustrated oversized method starts with nine 5 1/2 in squares from each fabric. Trim the sewn units to 5 in, aligning the ruler’s diagonal with the seam. You get 18 units, one spare. The traditional 5 3/8 in start has less trimming room. Check both test units and print direction before chain piecing. This method does not apply to the hourglass mode.
Hourglasses take a second diagonal operation
Hourglass / QST
Pair one starting square from each fabric. Sew a quarter-inch on both sides of a diagonal, cut on the line, and press the two intermediate HSTs.
Keep those HSTs untrimmed except for dog ears. Pair them with contrasting triangles opposite and seams nested; mark the perpendicular diagonal.
Sew a quarter-inch on both sides, cut and press. Trim the final four-triangle squares with their seam intersection at the exact stated midpoint. Sew and measure a test pair before a full batch.
A few things to check
Is the yardage for both fabrics combined?
The purchase amount is per fabric. Buy that amount of fabric A and the same amount of fabric B, using the same usable width for each.
What happens when I need an odd number?
The tool rounds up to a whole pair of starting squares. You will have one spare HST when the requested count is odd.
Why is there a trimming allowance?
Extra on the starting square gives some room to square up the sewn unit. It is added beyond the usual finished size plus 7/8 inch. Sew a test before cutting the whole batch.
Does this cover four- or eight-at-a-time HSTs?
The HST mode uses the two-at-a-time method with quarter-inch seams. Four- and eight-at-a-time HST recipes are not included; the hourglass mode has a separate two-stage recipe.
Can I use the HST starting-square recipe for hourglasses?
No. The second diagonal operation needs its own allowance. Select the named hourglass convention and keep the intermediate HSTs untrimmed.
Is the trimming midpoint rounded to an eighth?
No. It is exactly half the final unfinished side. A 3 7/8-inch unfinished square has a midpoint of 1 15/16 inches.
What is the purchase amount for two colors?
Each fabric has its own square count and purchase amount. Buy the stated quantity from fabric A and again from fabric B.
Has a physical test batch been sewn for this tool?
No. The arithmetic has been checked, but physical sew-out has not been performed. Verify trim coverage with your fabric, seams and pressing before a full batch.
