Calculating fabric for a quilt can feel like a puzzle at first, but once you get the hang of it, it’s a total game-changer for your projects. Whether you’re a beginner or a seasoned quilter, knowing how much fabric you need is crucial to making sure your quilt turns out just right. This guide will walk you through the simple steps to calculate fabric yardage, helping you avoid running out of fabric or buying too much.
Getting your fabric calculations right can save you time, money, and a lot of frustration. From figuring out quilt size to determining fabric needs for the top, backing, and binding, we’ve got you covered. Ready to dive in? If you’re curious about how cotton fabric is made, check out our guide on its journey from field to fabric!
How to Calculate Fabric for a Quilt: Step-by-Step Guide
Step 1. Determining the Quilt Size
Before you dive into selecting fabric, you need to determine the size of your quilt. Whether you’re planning a cozy lap quilt or a large bedspread for a king-sized bed, knowing the right dimensions is essential for calculating how much fabric you’ll need. Let’s break it down!
Common US and UK Quilt Sizes
Here’s a quick reference for common quilt sizes in both the US and UK:
| Size | US Dimensions (inches) | UK Dimensions (inches) |
|---|---|---|
| Twin | 66 x 90 | 66 x 90 |
| Full/Double | 80 x 90 | 78 x 84 |
| Queen | 90 x 102 | 90 x 102 |
| King | 104 x 110 | 108 x 120 |
You can adjust these sizes depending on your specific preferences. For example, if you’d like the quilt to hang lower over the edges or cover the bed more fully, simply add extra inches.
How to Measure Your Quilt
- Measure the Mattress Length, Width, and Height
Start by measuring the length and width of the mattress. For bedspreads, don’t forget the height, especially if you want the quilt to drape over the sides of the bed. Measure from the top of the mattress down to the floor to determine how much you want to hang. - Decide How Much Fabric to Add for Hanging Down Below the Edges
After measuring the mattress, consider how far down you want the quilt to hang. If you want it to drop 12 inches on each side, add this to your quilt’s length and width measurements. - Add Extra Fabric for Borders or Design Features
Keep in mind any additional design elements like borders or sashing. For borders, add an extra 6-10 inches on each side, depending on how wide you’d like them to be. - Sketch Your Quilt Design
Drawing your quilt design is a great way to visualize the final look and better estimate fabric needs. Whether you’re using a simple grid or a more intricate pattern, sketching helps you stay on track with fabric calculations.
Step 2: Calculating Fabric for the Quilt Top
Estimating Fabric for Quilt Blocks
The first thing you need to do is decide what size your quilt blocks will be. Common block sizes include 4, 5, or 6 inches, but you can choose any size that fits your pattern. Once you’ve chosen your block size, you’ll start estimating the fabric required for each.
For instance, if you’re using 5-inch blocks for a quilt that’s 90 inches by 102 inches (a queen size), divide the width and length of the quilt by your block size. This gives you a rough idea of how many blocks you’ll need. Keep in mind, blocks are often cut a bit larger than their finished size to allow for seam allowances.
Deciding the Number of Blocks and Their Size
To calculate the number of blocks, divide the quilt’s dimensions by the block size. If your quilt is 90 inches wide and you’re using 5-inch blocks, divide 90 by 5. That gives you 18 blocks across. Do the same for the length, rounding up if necessary. This ensures your quilt is fully covered.
Adding Extra Fabric for Seams
Don’t forget about seam allowances! A typical seam takes up about 1/4 inch, so you need to add some extra fabric for each block. If your blocks are 5 inches, add 1/2 inch to account for the seam allowances on both sides. It’s a small addition, but it ensures everything fits together perfectly.
Example of Calculating Yardage Based on Square Blocks
Let’s walk through an example. For a quilt with 5-inch blocks, suppose you need 20 blocks across the width and 24 blocks down the length. That’s 20 x 24 = 480 blocks in total. Each block needs about 5.5 inches of fabric to account for seams.
Multiply 480 blocks by 5.5 inches to get 2,640 inches of fabric. Now, convert that to yards by dividing by 36 inches—so, you’ll need about 73 yards of fabric for the quilt top. Keep in mind, this is just an example—you can adjust based on your own block sizes!
Adding Fabric for Design Elements
If you’re including sashing, borders, or cornerstones, make sure to add fabric for those elements. For example, if your quilt has borders around the edges, calculate the total length of your quilt (including all sides) and how much fabric is needed for the strips. You’ll need about 3-5 inches extra fabric per border, depending on how wide you want them.
Pieced Designs vs Solid Block Designs
The fabric needed will also differ depending on your design. Pieced blocks (with multiple fabric pieces per block) generally require more fabric than solid block designs, where each block is one piece of fabric. If you’re using a pieced design, factor in the extra fabric for each section of the block.
Step 3: Calculating Fabric for the Quilt Backing
The quilt backing is an essential part of your project—after all, it’s the final piece that holds everything together! To make sure you have enough fabric to cover the whole quilt, it’s important to calculate properly. The backing needs to be slightly larger than the quilt top to allow for seams and any potential stretching during quilting.
Understanding the Size of Quilt Backing Fabric Needed
Measuring the finished size of your quilt top. For instance, if your quilt top measures 90 inches by 102 inches (a typical queen size), the backing should be at least that size, but you’ll want to add a bit more to make sure it covers all sides and gives you enough room for quilting.
Measuring Your Quilt’s Finished Size and Adding Extra for Seams
Once you have the dimensions of your quilt top, add a few extra inches to account for seam allowances and any slight shrinkage during the quilting process. I recommend adding about 4-6 inches to both the length and width of your quilt. For example, if your quilt top is 90 inches by 102 inches, you’ll want a backing that’s 96 x 108 inches to give yourself a little breathing room.
Common Backing Fabric Widths and How to Calculate for Them
Backing fabric usually comes in wider widths (typically 90 inches, also known as wide backing fabric), so for most quilts, you may not need to piece it together. However, if your quilt is larger than the width of the fabric, you’ll need to sew two or more pieces together.
For example, if you’re working with 90-inch wide fabric, and your quilt is 96 inches long, you’ll need a piece of fabric that’s 96 inches long. But be sure to check the width—if it’s not wide enough, you’ll need to sew extra pieces together to get the correct width.
How to Piece Together Backing Fabric if It’s Smaller Than Your Quilt Size
If your backing fabric is smaller than your quilt, don’t stress—it’s easy to piece together! Let’s say your fabric is 45 inches wide (a standard width). To create the backing, you’ll need to sew two pieces together lengthwise.
For instance, if your quilt is 90 x 102 inches and your fabric is 45 inches wide, you’ll need to sew two 45-inch wide pieces together to cover the width of the quilt. Afterward, you’ll just need to ensure the length of your fabric is sufficient to cover the whole quilt.
Example of How to Calculate Backing for Large Quilts
Here’s a real-world example: Suppose you’re working on a king-sized quilt with a finished size of 110 x 120 inches. You plan to use 90-inch wide fabric for the backing.
- Width: The quilt is 110 inches wide. Since your fabric is 90 inches wide, you’ll need two pieces of 90-inch wide fabric sewn together to cover the width. Each piece should be 110 inches long.
- Length: The quilt is 120 inches long, so you’ll need one piece of fabric that’s 120 inches long to cover the full length.
This means you’ll need 2 pieces of 90-inch wide fabric, each 110 inches long, and 1 piece of 120 inches long fabric to complete your backing.
Step 4: Determining Yardage for Borders and Sashing
Borders and sashing bring the finishing touch to your quilt, but they require accurate yardage calculations to avoid running out of fabric.
How to Calculate the Amount of Fabric for Quilt Borders
Measuring the perimeter of your quilt. To find the perimeter, add the quilt’s length and width, then multiply by 2.
For example, if your quilt is 90 inches long and 102 inches wide, the perimeter is:
(90 + 102) x 2 = 384 inches.
Next, decide on the border width, typically between 4 and 6 inches. Multiply the perimeter by the border width.
For a 4-inch wide border:
384 inches x 4 inches = 1,536 inches. Convert that to yards (divide by 36 inches), so you’ll need about 42.67 yards for the border.
Remember to add extra fabric for seams to avoid running short.
Sashing Fabric Calculations
Now, let’s calculate the fabric for sashing, which goes between the quilt blocks. Determining how many strips and their length.
Let’s assume your quilt has 20 blocks across and 24 blocks down, and each block is 6 inches by 6 inches.
For vertical sashing (between rows of blocks), each strip is 6 inches wide and the length of your quilt. If your quilt is 90 inches long, you’ll need 90-inch strips for each of the 24 rows. That’s 2,160 inches of fabric for vertical sashing.
For horizontal sashing (between columns of blocks), each strip is 6 inches wide and 102 inches long. Multiply 102 inches by 20 strips (one for each column), giving you 2,040 inches of fabric.
Add both measurements:
2,160 inches + 2,040 inches = 4,200 inches.
Convert to yards (divide by 36 inches), so you’ll need about 116.67 yards of fabric for the sashing.
Different Sashing Designs and How They Affect Fabric Yardage
The sashing design impacts how much fabric you’ll need. Simple sashing requires less fabric, but if you opt for pieced sashing or sashing with cornerstones (small blocks at intersections), you’ll need extra fabric to account for those pieces.
For pieced sashing, add fabric for each small piece that forms the pattern. If your sashing has cornerstones, calculate extra fabric for those too. Wide or embellished sashing also needs more fabric.
Step 5: Special Quilt Components
Let’s talk about some special quilt components, like binding and setting triangles. These pieces are essential for giving your quilt that polished finish, so it’s important to calculate the fabric you’ll need for them.
Fabric Requirements for Binding
Binding is the fabric strip that finishes the edges of your quilt, giving it that clean, professional look. Binding is typically cut between 2 to 2.5 inches wide, but feel free to adjust based on your preference. It’s usually cut on the bias to give it some stretch, especially if your quilt has curves.
To figure out how much fabric you need for binding, you’ll calculate using the perimeter of your quilt. Measure the length and width of your quilt top, add them together, and multiply by 2 to get the perimeter.
For example, if your quilt is 90 inches long and 102 inches wide, the perimeter would be:
(90 + 102) x 2 = 384 inches.
Next, divide the perimeter by the width of your binding strip. If you’re using a 2.5-inch wide strip:
384 inches ÷ 2.5 inches = 153.6 inches.
Now, convert that into yards by dividing by 36 inches:
153.6 ÷ 36 = 4.27 yards.
So, you’ll need about 4.3 yards of fabric for the binding. It’s always a good idea to grab a little extra fabric just to be safe!
Fabric for Setting Triangles (On-Point Layouts)
If you’re using an on-point layout (where blocks are rotated 45 degrees), you’ll need extra fabric for the setting triangles that go in the corners and along the edges. These triangles are key to keeping your quilt in shape and making sure it fits together perfectly.
To figure out how much fabric you need for setting triangles, you’ll want to know your quilt’s dimensions and the size of your blocks. The number of triangles you’ll need will depend on your design, but in general, you calculate the triangle size based on the block size, then add extra for seams.
For example, if you have 6-inch blocks and you’re making a queen-sized quilt (90 x 102 inches), you’ll need enough fabric to cut the setting triangles. You might need a special template to get the right angle and size, depending on your quilt design.
Usually, setting triangles are cut from a larger piece of fabric, often from the same fabric as the background or borders. Be sure to add about 25% extra fabric to account for mistakes or adjustments, especially since bias-cut fabric can stretch or shift.
Decoding Fabric Measurements
Knowing common fabric measurements helps you make smarter yardage decisions. Here’s a quick guide:
Standard Fabric Bolt Width:
The standard fabric width on a bolt is typically 42-44 inches, although some specialty fabrics (like backing) may be wider. This affects your yardage calculations, especially when cutting wide strips for borders, sashing, or backing.
Width of Fabric (WOF):
The Width of Fabric (WOF) is the full width when you buy it off the bolt. Usually, it’s 42 to 44 inches wide, but always check. WOF is key when calculating yardage because it tells you how many strips you can cut across the fabric’s width. This helps prevent waste.
Charm Squares, Fat Quarters, and Long Quarters:
- Charm Squares are 5 inches by 5 inches and are perfect for small blocks or quick designs.
- Fat Quarters are 18 inches by 22 inches and work great when you need a little more versatility.
- Long Quarters are 9 inches by 22 inches and are ideal for smaller projects or specific design elements.
Converting Fabric Measurements (Inches to Centimeters):
Sometimes you’ll need to convert inches to centimeters (or vice versa). The formula is simple:
Inches x 2.54 = Centimeters
Centimeters ÷ 2.54 = Inches
Conclusion
Now that you’ve walked through the steps of fabric calculations, you’re ready to dive into your quilting project with confidence. Start by determining your quilt size and calculating fabric for the quilt top, backing, borders, and special components like binding and setting triangles. It might seem like a lot, but once you break it down, it’s much easier than it seems!
If you’re a beginner, don’t worry if it feels a bit overwhelming at first. Keep practicing, and soon you’ll be able to tackle any quilt project with ease. Ready to start? Head over to F&A Fabric for a wide selection of top-quality quilting fabrics and get your next quilt underway. Happy quilting!
