A lone star is eight big diamonds, each strip-pieced from rings of small ones, and the whole quilt hangs on one choice: the star’s size. Enter it and the rings; the strip width, the cut angles, and the background pieces follow.
Your Star
Cut Strips At
2 ⅜in
for a 36″ star · 4 rings · big diamond edge 10.5″
Slice every strip set at 45°, 2 ⅜″ apart: each slice is one row of a big diamond. Starch before cutting; every edge is bias.
- Small diamond edge2.64 in
- Strip setssew 4 fabrics per set, offset by one width
- 45° slices needed32 (4 per diamond × 8)
- Strips per fabric, about14
- Background corners4 squares ≈ 13 ¾″
- Background sides4 QSTs from a 16 ¼″ square
The Formulas
big diamond edge = star size ÷ 3.414 · small diamond edge = big edge ÷ ringsstrip cut width = small edge × 0.707 + ½ · strips sew into sets, cut again at 45°The 3.414 is the star’s geometry: eight 45° diamonds meet at the center, and the star’s width runs 2 × (1 + cos 45°) big-diamond edges. The 0.707 converts a diamond’s edge to the strip width that cuts it: a 45° diamond is wider along its edge than across it.
Worked Example
A 36 in star, 4 rings:
- Big diamond edge: 36 ÷ 3.414 = 10.5 in. Small edge: 10.5 ÷ 4 = 2.64 in.
- Strip width: 2.64 × 0.707 + ½ = 2⅜ in: many quilters cut 2½ and float the extra.
- Four fabrics ring the diamonds: sew 4-strip sets, slice at 45° every 2⅜ in, and each slice is one row of a big diamond.
- Background: four squares and four QSTs sized from the diamond edge, listed in the result card.
Strip-Piecing the Diamonds
- Offset each strip in the set by one strip-width so the 45° slices use the whole set.
- Cut at exactly 45°, the ruler’s line on the seam, every slice. A degree off compounds eight times at the center.
- Press seams open or all one way per set, and pin every diamond-to-diamond match; the center eight-point meeting is the whole show.
Assumptions and Defaults
- The classic even-rings star: rings² small diamonds per big diamond, 8 × rings strips sliced per fabric position.
- Strip width rounds up to the ruler’s ⅛; the finished star then runs a touch generous, which the background absorbs.
- Background corner squares = star ÷ 3.414 × 1.3 and side QSTs sized to match: both oversize-and-trim friendly.
Lone Star Questions, Answered
What strip width do I cut for a lone star quilt?
The strip width for a lone star is the star size ÷ 3.414 ÷ rings × 0.707 + ½ in, so a 36 in star with 4 rings cuts 2⅜ in strips. Bigger stars or fewer rings mean wider strips, and the calculator rounds the result to the nearest ruler line.
How many fabrics and strips does a lone star need?
A lone star uses one fabric per ring position in the classic gradient, so 4 rings call for 4 fabrics. Each large diamond takes one 45° slice per ring, with eight diamonds in each star, and the result card counts the strips you need of each fabric.
Why does the center of my lone star hump?
A lone star center humps because eight bias seams meet there, so any stretched edge piles up at that point. Starch the strip sets, cut true 45° angles, pin every match, and press the final joins open; a slight hump usually presses flat, whereas a large one means a seam allowance drifted.
What goes around a lone star?
A lone star is set with four corner squares and four side triangles, cut as quarter-square triangles so the quilt’s edge stays on the straight grain, all from the background fabric. Their sizes appear in the result card, and cutting them generously, then trimming the top square, gives the neatest finish.