Quilt math · Calculator
Lone Star quilt math
How big a Lone Star comes out from the strips you cut, and the strip sets, rows and background pieces to make it.
The short answer
A Lone Star of 5 diamonds a side from 2½″ strips is about 48¼″ across, point to point. Set in its square it finishes at 49″: trim it to 49½″. You need 25 strips, 5 strip sets of 5.
Work out yours
Free · no account200 diamonds, about 2⅞″ a side · each point about 14⅛″ a side
About, point to point. Its square trims to 49½″, 49″ finished.
5 strip sets of 5, one fabric a ring. Each set uses about 38¾″ of a strip, so one 42″ strip of each.
4 corner squares cut 15″, and one 22½″ square cut twice on the diagonals for the 4 side triangles.
Quarter Inch’s “One big star” layout draws the star ring by ring and prints the strip sets in cutting order.
Start a Lone StarSame sums as the app: @quarterinch/cutting starStripSets · diamonds 45°, cut every strip-width at 45° · the square trimmed to the next ½″ with ¼″ beyond the points
How a Lone Star is made
A Lone Star is one big eight-pointed star. Each of its eight points is a large diamond made of small 45° diamonds: 5 a side makes 25 in each point and 200 in all. Rather than cut each small diamond, you sew strips into strip sets, cut the sets into rows at 45°, and sew the rows into points.
The star sits in a square. Four corner squares and four side triangles fill the gaps between the points, set in with Y-seams.
- Lone Star
- Le Moyne Star
Lone Star sizes
The square each star trims to, finished, by the strips you cut and the diamonds a side of each point:
| Diamonds a side | 1½″ strips | 2″ strips | 2½″ strips | 3″ strips |
|---|---|---|---|---|
| 3 a side | 15″ | 22½″ | 29½″ | 37″ |
| 4 a side | 20″ | 29½″ | 39½″ | 49″ |
| 5 a side | 25″ | 37″ | 49″ | 61″ |
| 6 a side | 29½″ | 44″ | 58½″ | 73″ |
| 7 a side | 34½″ | 51½″ | 68½″ | 85″ |
| 8 a side | 39½″ | 58½″ | 78″ | 97½″ |
| 9 a side | 44″ | 66″ | 87½″ | 109½″ |
Add borders to reach a bed size. Each figure is the star across, about, plus a little room so the points float clear of the seam, trimmed to a whole ½″.
How it’s worked out
| Strips cut 2½″ sew to (the diamond’s height) | 2″ |
|---|---|
| A diamond’s side: its height × √2 | about 2⅞″ |
| A point’s side: 5 diamonds | about 14⅛″ |
| The star across, point to point: a point’s side × (2 + √2) | about 48¼″ |
| The square, finished: the star and ¼″ each side, up to the next ½″ | 49″ |
| Trim the sewn square to (+ ½″) | 49½″ |
| Corner squares, cut | 4 × 15″ |
| Side triangles: one square cut twice on the diagonals | 22½″ |
You never cut by the diamond’s side. The side is about 2⅞″, never a ruler length. You cut by the strip’s width: every row is cut 2½″ from the last, measured square to the cut, with the ruler’s 45° line on the strip’s edge.
The strip sets
With 5 diamonds a side you sew 5 strip sets of 5 strips each. Each strip in a set is stepped 2″ along from the one above, so the 45° cuts run straight through the diamonds. Cut 8 rows from each set, one for each point: 40 rows in all.
A set uses about 38¾″ of each strip, so one 42″ strip is enough. In all you need 25 strips of 2½″. Painted ring by ring, the first fabric is at the center and the tips:
| Fabric | Strips of 2½″ |
|---|---|
| 1, center and tips | 2 |
| 2 | 4 |
| 3 | 6 |
| 4 | 8 |
| 5 | 5 |
Bigger stars, wider strips or more diamonds a side, need strips longer than one width of fabric: the calculator says when.
What changes the answer
- Your seam. Every one of the 200 diamonds has seams, and a seam a little too wide on each adds up across a point. Sew a test row and measure it against about 14⅛″ before you sew the rest.
- Bias edges. The rows are cut at 45°, so their edges stretch. Starch the strip sets before you cut and handle the rows gently.
- The background. The corner squares fill exactly to the trimmed edge. The side triangles are cut a little large and trimmed with the square, so the star floats clear of it.
A Lone Star in Quarter Inch
On New quilt, choose One big star. Pick the strips (1½″, 2″, 2½″, 3″) and the diamonds a side (3 to 9), and it fits a border to your bed size. The cutting chart gives the strip sets in order, the rows to cut and the background, as on this page.
Questions
Short answers.
Something else? A real person replies.
hello@quarterinch.app
How big is a Lone Star quilt?
It depends on the strips and the diamonds a side. 5 a side from 2½″ strips finishes at 49″ square, before borders.
What size strips for a Lone Star?
Any width works; Quarter Inch offers 1½″, 2″, 2½″, 3″. Each diamond sews to the strip less ½″, measured between its parallel sides.
How many diamonds are in a Lone Star?
Eight points of n × n. With 5 a side that’s 200.
Do I need Y-seams for a Lone Star?
Yes, to set in the corner squares and side triangles between the points. The points themselves are sewn in straight rows.