Whoever said you’d never use your math classes after high school was just plain wrong.
Quilting seems like such an innocent craft, until you make your first one and realize there can be a TON of math that you need to do to finish your quilt!
Even if you have a pattern you are working off of, they usually only get you as far as a finished quilt top. You can often be left to calculate your batting, backing, and binding requirements by hand in order to finish it up.
Regardless of whether you are making your first quilt or your hundredth, remembering the math and how to calculate these important parts of your quilt can be tough (or just annoying) to keep straight.
So today I’m going over how to calculate quilt backing yardage requirements for your quilt so you always get it right and never have to make a second trip to the fabric store again.
OH! And I’ve got a special surprise too, since math is just dumb in general, I’m getting rid of it! I’m also introducing my new backing batting and binding calculator today so if you don’t have time or just don’t want to calculate it by hand, you never have to again!
Introducing our new FREE Backing Batting and Binding Quilting Calculator
Sometimes technology is just easier and we just don’t want to do the math out by hand.
I get that, and totally sympathize with that.
That’s why we went out and created a free online quilt backing calculator to do it all for you with one click.
It not only calculates quilt backing yardage requirements for you, but also how much yardage you need for binding strips, how many strips you actually have to cut from that yardage, as well as what standard size of batting you’ll need for your project!
Super simple to use, and all the math done for you.
I’ll go into detail on this a bit more later, but if you just want to skip to the all-in-one backing batting and binding calculator, I wouldn’t blame you 😛
No email needed – check out our FREE Backing, Binding, and Batting Calculator here!
Calculating Quilt Backing – things to consider
While there aren’t a huge amount of things to worry about when it comes to your backing, there are a couple of things you want to keep in mind when you do your calculations.
Which direction do you want the fabric to run?
This is one many quilters learn the hard way.
You go to the fabric store and find the perfect backing fabric for your quilt, do some quick math to calculate quilt backing yardage for your current project while standing in line waiting for it to get cut, and then you get home and realize you didn’t get enough yardage for the fabric to run the direction you want.
instead of running the length of the quilt, you only have enough to run the short direction.
Now the fabric pattern feels off.
Depending on the direction the pattern runs you may need more (or less!) yardage to piece your backing fabric.
Getting it wrong leads to you to either spend too much money, force you to go back to the store, or settle on a pattern direction you don’t love.
Keeping the backing pattern direction in mind when calculating will help make sure you get it right the first time.
How much extra backing yardage should you have?
Our rule of thumb is 6 inch overage on every side.
Yes you’ll need a bit extra than just the amount to cover the quilt top. Cutting your backing to perfectly fit the size of your top is a recipe for exposed batting – and heartbreak.
It’s a must if you intend to send the quilt out for professional longarm quilting.
But if you quilt it yourself you’ll appreciate the overage to hold on to when you are quilting it on your domestic machine.
And when you baste it yourself you’ll know it doesn’t take much of a tilt to end up with your quilt top a little cock-eyed on the backing.
Too little backing yardage will mean that tilted quilt top might end up with a corner missing some batting and backing.
A bit of extra yardage will ensure it comes out perfect every time without redoing it twelve times.
Formulas to Calculate Quilt Backing – How many yards do you need?
Each quilt is different depending on its dimensions – here’s how you can calculate the quilt backing for your specific project depending on the direction you want the backing fabric to run.
To get started you’ll need two measurements from your quilt, the length of the shortest side and the length from the longest side, both in inches. Whatever the dimensions ended up being, add 12 inches to each for the overage.
For example if one of your side measured 72 inches, adding 12 will get you 84 inches.
This will give you 6 inches of fabric overage on each side.
Backing fabric running the short direction
We need to know how many widths of fabric you’ll need to run the short length of the quilt.
By dividing the longest edge by your WOF, you can find out how many rows of fabric you’ll need to piece together.
Once you know how many rows you need, multiplying it by the width you’ll need for each row, or your shortest side, will tell you how many inches long each row of fabric will need to be.
Once we know the full amount of inches we’ll need, we want to convert that number into yards to make it easy in the store.
36 inches = 1 yard.
Here’s the actual formula
(Longest length / 42) x shortest length = fabric yardage in inches
To turn that into yards:
Fabric yardage in inches / 36 = backing yardage required
You may need to round it up to the nearest 1/4 yard or half yard to make it easy to cut when you are in the store.
Already ready to throw the pen and paper down and search for an online calculator for this? We’ve got you! Skip the math and use our FREE backing batting and binding calculator instead.
Backing yardage running the long direction
To calculate the yardage going the opposite direction so it runs along the longest side of the quilt, take the formula from above and simply swap the longest length and the shortest length in the equation.
To run the opposite direction going the long way, we want to know how many rows of fabric we’ll need to span the short edge of the quilt. Then we simply multiple by the longest length to get the full yardage.
(shortest length / 42) x longest length = fabric yardage in inches
And then turning it into yards is the same:
Fabric yardage in inches / 36 = backing yardage required
How many yards of fabric do I need using 108 wide backing fabric
A magical thing exists to make backing yardage super easy – its 108” wide fabric made specially for quilt backings.
Why is that so awesome? For most quilts, it’s wide enough to cover the entire backing without having to piece it which means less yardage required.
The pattern direction might still matter though if it isn’t a solid fabric, so just keep an eye out for it.
Calculating 108” backing yardage running the short way
The formula is basically the same, the only difference is accounting for the change in the 108” width of fabric.
(shortest length / 108) x longest length = fabric yardage in inches
And then turning it into yards is the same:
Fabric yardage in inches / 36 = backing yardage required
You may find that your ( shortest length / 108 ) is less than 1, that’s okay, it just means you’ll be able to fit the full quilt on the backing fabric without piecing.
If you are doing large bed size quilts, either king or queens, you may find that the dimensions you have are larger than 108” requiring you to piece a backing even with the larger width of fabric.
That’s okay too, it’ll be a pieced backing still, just one with less seams in it compared to a 42” wof.
Calculating 108” backing yardage running the long way
You guessed it, the swap your two dimensions to run the opposite direction.
(longest length / 108) x shortest length = fabric yardage in inches
And then turning it into yards is the same:
Fabric yardage in inches / 36 = backing yardage required
If you aren’t sure if you got it all right, be sure to double check your math with our free quilt backing calculator here!
Calculating Batting
While it seems like there is a lot to think about when it comes to your backing, usually your batting is much simpler.
How to measure batting for a quilt
While many people like to get their batting in bulk on a large roll, most hobby quilters will opt for the standard cut prepackaged kind.
While buying in bulk can save you a lot of time and money when it comes to shopping for batting, buying batting in bulk will take up significant floor space in the house.
Often times it is much easier to just simply pick up a precut batting amount in your required size.
These precut sizes generally come in sizes aligned with making standard bed sizes. You’ll see sizes from a crib or baby size all the way up to a king size standard precut batting.
My go to is always the Quilter’s Dream Cotton blend and they make it super simple to figure out what size I need as long as I know my quilts finished dimensions. Not to mention their cotton is just oh-so-soft.
If you have been defaulting to the polyblends that are often found n the box stores, I highly recommend trying out Quilter’s Dream for a quilt to see the difference.
You can find it on Amazon here!
Quilt batting sizes
So what are the actual dimensions that the precut sizes come in?
We used Quilter’s Dream’s precut sizes as a rule of thumb and created this size chart below for you to refer back to next time you are in the market for some batting!
| Size | Short Side (inches) | Long Side (inches) |
|---|---|---|
| Craft | 36 | 46 |
| Crib | 46 | 60 |
| Throw | 60 | 60 |
| Twin | 72 | 93 |
| Double | 93 | 46 |
| Queen | 93 | 108 |
| Super Queen | 93 | 121 |
| King | 122 | 122 |
You can also use our FREE backing batting and binding calculator which also calculates batting size for you!
The quilt backing calculator will automatically compare the precut standard sizes for you to tell you the smallest size batting you can get away with for your project.
Should batting be the same size as the quilt top
No. Giving yourself some wiggle room in your batting dimensions will make a world of difference when you go to baste.
Basting is not exactly a science and there is definitely a good amount of error when you are securing the quilt sandwich layers together.
Cutting your batting exactly to the same size as your quilt top takes away all that wiggle room and means you have to be PERFECT in your basting in order to make sure you have batting under ever bit of that quilt top.
And even if you are able to get it basted perfectly, when you machine quilt, there can be some smooshing, and stretching of the quilt top a bit making it a bit larger in some places and smaller in others.
This means that even if you are perfect going into quilting, you may not be perfect after quilting.
Not to mention it’ll be a pain in the butt to quilt around the edges since you won’t have anything to hold on to under the sewing machine. Your presser foot will constantly be falling off the edge of the quilt.
So save yourself a lot of frustration and give yourself some overage around the edges of your quilt in your batting as well.
The step after quilting it is to square the quilt up so it has beautiful 90deg corners where you’ll be trimming all the excess off anyway – so where you feel like you might save yourself from performing that squaring step, and saving a little bit on material, you’ll end up adding time (and frustration) to the basting step.
Not worth it in my opinion.
If you want a quick refresher on how to square a quilt, be sure to check out our tutorial here!
How much extra batting should you have?
You can play around with how much overage you like, however 4” overage all around the outside of the quilt is a good place to start.
This gives me plenty to hold on to when I’m quilting the edge of the quilt in my domestic machine, while avoiding wasting TOO much material at the same time.
Hint: you can save scraps of batting and stitch them together for other projects later! Check out this tutorial on Frankenbatting from National Quilter’s Circle here!
I also like 4” overage for batting because it gives me a couple of inches around the outside of the batting to see my backing still.
If you’ve read my post on how to baste a quilt, you might remember that I try to use seams in the pieced backing as reference for getting my quilt top as aligned as possible with the backing material.
This helps keep the pattern of the backing material running straight down the back of the quilt instead of diagonally across by accident.
Having the batting slightly smaller than the backing allows you to see the seams of the backing so you can get the best chance possible at a perfectly basted quilt sandwich!
Take all the math and stress out with the quilt backing calculator
Don’t let me fool you, basting is definitely one of the quicker and easier steps to get right of the quilt making process.
Not having enough material in your batting and backing is the only thing that can make the process difficult and stressful causing you to set and re-set your quilt top to make sure all three layers are throughout the entire quilt top.
Making sure you have the right amount of yardage makes it super simple and using our new FREE quilt backing calculator is the perfect way to make sure you get the yardage right the first time – no math required.
There’s no email or other opt in required to use it, so be sure to bookmark it in your browser so you can find it easily the next time you need it!
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