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Calculating Fabric Amounts for Your Quilt Project

One of the most frustrating things about making a quilt is running out of fabric before you’re done. Once you’ve chosen the quilt size you want to make and have checked the dimensions, the next step is calculating how much fabric you need. In this guide, we look at some common quilt sizes and the amounts of fabric needed for all of the pieces.

Your Quilt’s Dimensions

The first step is to pick out what size quilt you want to make. Once you do that, you need to make sure that the dimensions work—for instance, if you have a bed that sits high off the floor, you will need a longer quilt. But first, start with the standard dimensions. Here are the dimensions for several different sizes of quilts.

Lap Quilt

A lap quilt can have many purposes. It’s a great size for a baby’s crib quilt, for hanging on the wall, or, my favorite, for putting over your lap when you’re cold.

How to Calculate Fabric Amounts for a Lap Quilt

Twin Size

How to Calculate Fabric Amounts for a Twin Size Quilt

Full Size

How to Calculate Fabric Amounts for a Full Size Quilt

Queen Size

How to Calculate Fabric Amounts for a Queen Size Quilt

King Size

How to Calculate Fabric Amounts for a King Size Quilt

Estimating Fabrics, or How Many Pieces Can I Get From a Yard?

There will come a time when you will have to calculate how much fabric you need to purchase for a quilt project. One quilt block may have many pattern pieces that fit together to make the 12-inch square. The following strategy will help you calculate the amount you need for each pattern piece in a quilt block. If you are creating a quilt that repeats one type of block, you will have many similar pattern pieces (for example, when making a Double Nine Patch lap quilt). It has four 4-inch squares of the dominant color and four 4-inch squares of the accent color. Let’s figure out how much fabric you will need of each color.

How to Calculate Fabric Amounts for a Double Nine Patch lap quilt. A Double Nine Patch lap quilt.
  1. Count the number of pattern shapes you need for one block. Measure and add on the ¼-inch seam allowances to get the true size. (For each Double Nine Patch you need four 4½-inch squares of the dominant color and four 4 ½-inch squares of the accent color.)
  2. Determine how many of these pattern pieces you will need for the entire quilt. (There are four squares of dominant colors in each block of the Double Nine Patch, and there are six blocks in the quilt, so you’ll need 24 4½-inch squares.)
  3. Measure the width of your fabric. Usually it’s 44 inches.
  4. Find out how many pattern pieces (with seam allowances added on) will fit across the fabric width. Divide the fabric width by the width of the pattern piece. (Forty-four inches divided by 4½ inches of the Double Nine Patch square is 9.7—but wait—you can only fit nine whole square pattern pieces in the width.)
  5. To determine the length of fabric needed and how many rows are needed to fit all the squares in, first divide the total number of pattern pieces by the number of squares that fit across the width of the fabric. (Remember, we need 24 squares for the lap quilt, and 24 divided by 9 is 2.6 rows. You’ll have to allow for three whole rows of fabric.)
  6. Then multiply that number of rows by the length of the pattern piece, including the seam allowance. (Multiplying the 4½ inches of the Double Nine Patch square by three rows yields 13½ inches.)
  7. To figure out how many yards are needed, divide the total inches by 36 inches (for the yard). Add on a 4- or 5-inch “fudge factor” to allow for mistakes. (For the Double Nine Patch, 13½ inches are needed for the rows plus a 4-inch fudge factor to equal 17½ inches. So approximately 18 inches divided by 36 inches equals half a yard. You will need half a yard of the dominant color and half a yard for the accent color.)
How to Calculate Fabric Amounts for a Quilt Project: How many Double Nine Patch squares will fit?

Do Your Math: Calculate the Right Amount

See how many Double Nine Patch squares will fit on the fabric.

Now that we know the fabric yardage you need to buy for a specific pattern piece or template of your quilt, let me show you how these amounts can be put together. There are ways that you lay out your patterns, dovetailing them with borders and lattices to save fabric. I try to use every scrap of my material. It is difficult to estimate the exact amount of fabric for a sampler quilt, because each patch is different. The following table gives you an educated guesstimate for fabric yardage. Backing and batting are not included, but your pattern likely will give you this information.

Fabric Guesstimates to Purchase for Entire Project
Quilt Size Color What Is Included Fabric Yardage*
Lap Dominant Blocks, lattice 2
Contrast Blocks, borders 2
Blenders Blocks (two fabrics) ½ each
Blocks and corner squares (one fabric) ¾
Background Blocks 1
Twin Dominant Blocks, lattice, border B 4
Contrast Blocks, border A
Blenders Blocks (two fabrics) ¾ each
Blocks and corner squares (one fabric) 1
Background Blocks 1 ¾
Full Dominant Blocks, lattice, border B 4 ½
Contrast Blocks, border A 3 ¾
Blenders Blocks (two to four fabrics) ¾ each
Blocks and corner squares (one fabric) 1
Background Blocks
Queen Dominant Blocks, lattice, border B 5
Contrast Blocks, border A 4
Blenders Blocks (two fabrics) 1
Blocks and corner squares (one fabric) 1⅝
Background Blocks 2
King Dominant Blocks, lattice, border B
Contrast Blocks, border A
Blenders Blocks (two fabrics) 1¼ each
Blocks and corner squares (one fabric)
Background Blocks

*Remember, these are estimates—not everybody cuts wisely.

Sometimes it’s necessary to know the amount of fabric to purchase for a specific part of your quilt. I can’t tell you how many times I’ve had to go back to the store and buy a different fabric for a lattice or border because the one that I purchased wasn’t quite right. Occasionally some quilters wait to see how the patches look before choosing the border fabric. If that happens to you, I’ve calculated how much fabric you’ll need for each section of your quilt. So get out your pad and pencil and let’s see what you’ll need.

To use this table, locate the section of the quilt that you need to purchase fabric for, perhaps it’s the lattice. Then look for the quilt size you are making, let’s say full size, and determine the yardage you should buy.

In your quilt, you may have several blender fabrics. One blender fabric should include all the colors of your color scheme. Others will be of different values of the dominant and accent colors. You can have as many blenders as you want; I’ve suggested the minimum.

Yardage for a Specific Part of a Quilt
Part Quilt Size Number Needed and Size Yardage
Lattice Lap 17 (3” × 12”) ¾
Twin 38 (3” × 12”)
Full 38 (4” × 12”) 2
Queen 58 (3” × 12”)
King 71 (4” × 12”)
Corner Squares Lap 12 (3” × 3”) ¼
Twin 24 (3” × 3”) ½
Full 24 (4” × 4”)
Queen 35 (3” × 3”)
King 42 (4” × 4”) ¾
Borders Lap 4” 1
Twin 10” or
A: 4”
B: 6”
Full 14” or 3
A: 6”
B: 8”
Queen 10” or
A: 4”
B: 6” 2
King 8” or
A: 3” 2
B: 5”
Background Fabric Lap 6 blocks 1
Twin 15 blocks
Full 15 blocks
Queen 24 blocks 2
King 30 blocks
Blenders Lap 2 or 3 fabrics ½ to ¾ of each
Twin 3 fabrics ¾ to 1 of each
Full 3 to 5 fabrics ¾ to 1 of each
Queen 3 to 5 fabrics 1 of each
King 3 to 5 fabrics 1½ of each

Now that you’ve decided on your project, done the arithmetic, and calculated the amount you need to purchase, it’s time for the fun part—picking out the fabric. Next stop—the fabric store! Have fun, and happy quilting!

From The Complete Idiot’s Guide to Quilting Basics by Laura Ehrlich