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On-Point Quilt Layout Calculator — Blocks, Setting Triangles & Size

~1 minute

Enter how many blocks are across and down in your on-point (diagonal) layout and the finished block size. The calculator returns the total block count, the side and corner setting triangles needed (with cut square sizes), the finished quilt dimensions, optional borders, and the yardage to buy for the setting triangles.

What this calculator determines

It calculates the total block count, side and corner setting triangles, cut square sizes, finished dimensions, and setting-triangle yardage for an on-point (diagonal) quilt layout.

Related calculators

Setting Triangle Calculator

Cut sizes, counts, and yardage for side and corner setting triangles in on-point quilts

Quilt Block Layout Calculator

How many blocks fit and how to arrange them, with sashing and borders

Quilt Block Size Calculator

Cut size for a finished block — finished size plus two seam allowances

Quilt Size Calculator

Finished quilt dimensions from block size, layout, sashing, and borders

Quilt Border Calculator

Border fabric yardage for straight borders, single or multiple

Examples

5×5 on-point, 6″ blocks, 2″ borders

5 across × 5 down, 6″ blocks, 2″ borders, 42″ fabric

Calculation

  1. Total blocks: 5 × 5 = 25
  2. Side triangles: 2×4 + 2×4 = 16; corner: 4
  3. Side cut square: (6×√2)+1.25 = 9.735 → 9.75″ (4 per square → 4 squares)
  4. Corner cut square: (6÷√2)+0.875 = 5.118 → 5.125″ (2 per square → 2 squares)
  5. Finished: (9)×6/√2 = 38.18″ + 2×2″ borders = 42.18″ square
  6. Setting-triangle fabric: 0.271 + 0.142 = 0.413 yd → buy 0.5 yd

25 blocks, 16 side + 4 corner triangles, 42.18″ square — buy 0.5 yd setting fabric

4×5 on-point, 6″ blocks, no borders

4 across × 5 down, 6″ blocks, no borders, 42″ fabric

Calculation

  1. Total blocks: 4 × 5 = 20
  2. Side triangles: 2×3 + 2×4 = 14; corner: 4
  3. Finished width: (7)×6/√2 = 29.70″; length: (9)×6/√2 = 38.18″

20 blocks, 14 side + 4 corner triangles, 29.70″ × 38.18″

Assumptions & Conventions

Block count
Total blocks equal blocks across × blocks down on the diagonal grid.
Finished dimensions
Finished width and length use the standard on-point formula (2n − 1) × block ÷ √2, with borders added on both sides if included.
Cut rounding
Cut squares are rounded up to the next 1/8″ and the combined yardage up to the next 1/8 yard.

Frequently asked questions