Calculate fabric yardage for any quilt size. Plan cutting layouts for squares, strips, and triangles with seam allowance and waste factor.
One of the biggest challenges in quilting is calculating how much fabric to buy. Buy too little and you can't finish the project (and the same dye lot may be gone). Buy too much and you waste money and storage space. This quilt calculator takes your desired quilt size, block arrangement, and seam allowances, and tells you exactly how much fabric you need for the top, backing, batting, and binding.
The calculator handles the most common quilt constructions: simple patchwork squares, strip quilting, half-square triangles, and log cabin blocks. It accounts for the 1/4" seam allowance used in quilting, fabric shrinkage (3-5% for cotton), and a configurable waste factor for cutting imperfections. It also calculates backing fabric, which often requires seaming panels together since quilting cotton is only 42-44 inches wide.
Whether you're making a baby quilt (36×52"), a throw (50×65"), or a king-size bedspread (105×105"), this tool eliminates guesswork and gives you a cutting plan before you ever visit the fabric store.
It helps you estimate the fabric, backing, and batting before you buy, which is the easiest way to avoid dye-lot problems and mid-project shortages. That extra planning is especially useful when borders, directional prints, or oversized backing can change the cut list quickly. It also gives you a more reliable shopping list before you start cutting blocks or committing to a final layout.
Blocks across = quilt width ÷ block size (rounded up if with sashing). Cut size = finished block size + (2 × seam allowance). Blocks per fabric width = floor(42" ÷ cut size). Rows needed = ceil(total blocks ÷ blocks per width). Yardage = rows × cut size ÷ 36. Backing yardage = 2 × (quilt length + 8") ÷ 36 (for quilts wider than 42").
Result: 80 blocks, ~2.5 yards total top fabric, 4.0 yards backing
Throw quilt (50×65") with 6" blocks needs 8×10 = 80 blocks. Cut size 6.5". 6 blocks fit per 42" width. 80÷6 = ~14 rows. Each fabric gets ~27 blocks. Backing needs two panels of 73" = ~4.0 yards.
The overall quilt dimensions determine how many blocks, strips, or units you need across and down. From there, the cut size adds seam allowance back in, because quilting is planned around the finished block but cut from larger pieces. That distinction is the source of many beginner mistakes.
Two quilts with the same finished size can require different yardage if one uses simple squares and the other uses triangles, directional prints, or multiple accent fabrics. Once shapes stop nesting efficiently, waste increases. The calculator gives you a practical estimate before you commit to a shopping list.
The top is only part of the material plan. Backing usually needs extra width and length so the quilt sandwich can be loaded, trimmed, and squared up after quilting. Adding a little buffer for shrinkage, test blocks, and cutting mistakes is usually cheaper than trying to source a matching print later.
Buy 10-15% extra beyond the calculated amount. This accounts for cutting mistakes, shrinkage (3-5% for unwashed cotton), and having fabric for test blocks. If you're a beginner, consider 20% extra.
Baby: 36×52". Lap/throw: 50×65". Twin: 70×90". Full/double: 85×90". Queen: 90×95". King: 105×105". Add 10-15 inches per side for a "drop" that hangs over the mattress.
Standard quilting cotton is 42-44 inches wide on the bolt. Usable width after trimming selvages is about 40-42 inches. Wide backing fabric comes in 108" widths, eliminating seams for most quilt sizes.
Buy batting at least 4 inches larger than your quilt top on all sides (8" wider and 8" longer total). For a 50×65" throw, you need at least 58×73" of batting.
If your quilt is wider than 42", you need to seam backing panels. For a 50-80" wide quilt, use two widths of fabric. Yardage = 2 × (quilt length + 8") ÷ 36. For quilts over 80" wide, use three widths.
Most quilters recommend pre-washing to remove sizing and prevent post-quilting shrinkage. Wash in warm water, dry on medium. Budget an extra 3-5% yardage for shrinkage. Some quilters prefer the pucker effect of not pre-washing.