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How Many 18-inch Blocks for a Throw / Lap Quilt?
A Throw / Lap quilt (60″ × 72″) needs 6 blocks with standard sashing, or 12 blocks set without sashing.
Your Block Count
2″ sashing · 3″ border
Finished: 44″ × 64″
No sashing or border
Finished: 54″ × 72″
Layout with Sashing (2 × 3)
Each square = one 18-inch block. Gray gaps represent 2″ sashing.
Estimated Fabric (with sashing + border)
Estimates assume a 2-color block, 2″ sashing, 3″ border, and standard 44″ quilting cotton. Add 10–15% for error.
Planning a Throw / Lap Quilt with 18-inch Blocks
A Throw / Lap quilt typically measures 60 × 72 inches finished —the most popular quilt size — perfect for a sofa or wrapping around one person. Using 18-inch finished blocks with 2-inch sashing and a 3-inch border, you will need 6 blocks arranged in a 2 × 3 grid.
If you prefer a simpler layout without sashing — blocks set edge to edge — the same Throw / Lap quilt needs 12 blocks in a 3 × 4 arrangement, finishing at approximately54″ × 72″.
Choosing Your Sashing Width
Sashing frames individual blocks and brings the quilt top to the desired finished size with fewer blocks. Wider sashing (3–4 inches) gives a more open, airy feel; narrower sashing (1–1.5 inches) lets the blocks be the star. No sashing at all creates a seamless all-over pattern — especially effective with blocks that form continuous secondary designs when set edge to edge, like Pinwheel, Nine Patch, and Flying Geese.
Calculating Fabric for a Throw / Lap Quilt
The fabric estimates above assume two fabrics per block, standard 44-inch quilting cotton, and a seam allowance of ¼ inch. In practice, quilts made from many different scrappy fabrics will need different yardages for each fabric. Add 10–15% to all estimates to account for cutting waste, miscuts, and design changes.
For the backing, you will need the quilt top dimensions plus 4 inches on all sides. A Throw / Lap quilt top of approximately 44″ × 64″ needs a backing of at least 52″ × 72″. For quilts wider than 44 inches, backing fabric must be pieced or wide backing fabric (108 inches wide) used.