Loading…
Loading…
Equilateral-triangle quilt math in one place: enter your finished triangle height and target quilt size to get the triangle count, the strip width to cut (height + ¾"), triangles per strip, and total yardage — free, in your browser.
192 full triangles — 16 per row × 12 rows, plus 24 half-triangles to straighten the row ends. Finished top: 58.9" × 72" before borders.
Cutting
Cut WOF strips at 6¾″, then cut triangles with a 60° ruler (or template) — each triangle's cut base is about 7⅞″.
≈ 10 triangles per 40" strip → 20 strips total.
Fabric
About 3.75 yd total across all fabrics (rounded up to ⅛ yd). Split it by how many triangles each fabric contributes — e.g. 48 triangles each for a 4-fabric mix.
Rows sew side-to-side with ¼" seams; press seams open or alternate directions so the tips nest. Ruler brands differ slightly on tip trims — cut one test strip before committing yardage.
Cut strips at finished height + ¾", triangles per 40" of usable strip width:
| Finished height | Cut strip | Side (finished) | Triangles per strip |
|---|---|---|---|
| 3" | 3¾" | ≈ 3½" | ≈ 21 |
| 4" | 4¾" | ≈ 4⅝" | ≈ 16 |
| 4.5" | 5¼" | ≈ 5¼" | ≈ 14 |
| 5" | 5¾" | ≈ 5¾" | ≈ 12 |
| 6" | 6¾" | ≈ 7" | ≈ 10 |
| 8" | 8¾" | ≈ 9¼" | ≈ 7 |
Cut strips at the finished row height plus ¾ inch. For triangles that finish 6 inches tall (a 6-inch row), cut 6¾-inch strips, then cut triangles from the strip with a 60-degree ruler. The ¾ inch covers the seam allowance at the tip and base.
Divide the quilt width by half a triangle's side length and subtract one for the full triangles per row, then multiply by the number of rows (quilt height ÷ triangle height). Each row also needs two half-triangles to straighten the edges. The calculator above does this math for any size — a 60×72-inch throw in 6-inch triangles needs around 200 triangles.
A 60-degree triangle ruler sized taller than your strip width. Most brands work the same way — align the ruler's marked line with the strip edge and alternate the ruler's point up and down along the strip. Brands differ slightly on blunt-tip trims, so test one strip first.
Sew triangles into rows first, alternating point-up and point-down with ¼-inch seams — the offset 'dog ears' at each end guide alignment. Then sew rows together, nesting or pressing seams open. The triangle points sit ¼ inch inside the row seam, so they stay sharp after joining.
We may earn a commission on purchases made through these links, at no extra cost to you. Learn more.