We were going to call this tutorial: Bias Binding: Basics & Beyond, however, we decided to forgo the clever alliteration and instead focus on the key words we hear whenever we receive questions about this very hot topic: "How do you figure out how much fabric you need?" "How do you cut all the strips?" "How do you sew all the strips together?" "How do you put it on your project so it looks smooth and pretty?" "Why is the sky blue?" We've posted about bias binding before, and even have an older tutorial on the subject. But, it was time to take a fresh look and collect all the scattered tips and information into one updated article. We'll address all four of the most common questions: yardage, cutting, making and attaching. You're on your own for the blue skies!
Depending on whom you talk to, the word bias can have varied meanings. The official definition of bias is: an oblique or diagonal line. If you have a passion for sewing like us, as soon as you hear bias, you think of 45°, angle-cut fabric pieces or strips. If you hear bias in combination with binding or tape, you immediately envision a beautiful edge finish or trim. If you didn’t think of either of these things, but instead thought about how you were denied a place on prom court because certain people had it out for you... well... it's time for a fresh look at bias. This tutorial is for you!
We’ll be explaining: how to calculate the amount of fabric you need, how to determine the square size needed for the width of strips you will be cutting, how to join strips, which foot to use on your sewing machine, and, as always, a few tips we’ve discovered along the way. First, let's discuss why you even need to use bias binding or tape.
The main reason is because of the 45° angle cut, or bias cut. Cutting fabric on the bias makes it super pliable so it can curve into and around all kinds of shapes. For example, a woven fabric that characteristically has no stretch, will have stretch when it's cut on the bias. If you don’t believe us, grab a piece of woven fabric and pull it on the straight grain; then, pull it at an angle. The bias stretch makes it possible to go around corners and curves neatly and without bunching to create a professional finish. If you’ve only used straight grain binding up until now, once you try bias binding, you will be amazed at the difference!
Another reason we love bias binding is because it’s a very versatile trim and a fantastic way to finish the raw edge on just about anything. In home décor, you see it in various widths on quilts, blankets, pillows, curtains, table linens and more. It's used on garments around necklines, armholes, sleeve edges, etc. Basically, it’s the ideal technique to finish any raw edge, whether inside (also known as a Hong Kong finish) or along the outside edge of a sewn project. Not to mention, it's the foundation for making custom piping.
Third, it’s easy on your budget. You can make enough binding from a yard of fabric to go around a queen size quilt with some to spare; that’s a lot of binding for the money when you think about it.
Fourth, bias cut binding is known to be stronger than straight grain binding, making it ideal for items that will be washed regularly, such as table linens; or used heavily, such as a bed quilt.
Finally, you can use whatever fabric you want (even scraps) to create a beautiful custom finish. Although it takes time to crunch the numbers for all the details, and takes more time to actually make the bias binding, it’s well worth it in the end. Just take a look at some of our previous tutorials where we took the time to make custom binding in the Sew4Home studio.
Of course, you can buy ready-made bias tape, pre-folded and ready to go which we discussed in our tutorial Terrific Trims Take #2. In the Sew4Home studio, we usually end up making our own binding in order to get the perfect fabric combinations, but we’ve certainly used plenty of the pre-made kind too!
Determining length, width and yardage
Once you’ve made your fabric selection, you need to figure out how much of it you'll need. You’ll be happy to know there are easy formulas for determining this! But, first things first, you have to actually measure the item to which you plan to attach the bias binding.
Measure your project
Exactly where will you be attaching your beautiful bias binding? Measure the edge(s) of your project that will be bound. For example, if you plan to sew bias binding around a quilt that measures 36" x 36", you can simply use a tape measure to measure each side. Or, in this case, you can simply multiply 36" x 4, which equals 144". You'll need at least 144” of bias binding. We say "at least" because you have to consider turning the corners and finishing the ends. Therefore, it’s recommended you add 10" to 12" to your minimum measurement (you can add more if it makes you feel more comfortable, but don’t go too crazy; you’ll end up with more binding than you know what to do with). In our little example, the total length of bias binding we need is 144" + 12" = 156".
Width of the strips
You now know the total inches you need, but before you start cutting random strips of fabric, you have to figure out how wide they need to be. This is one of those areas where you have to make a decision based on what it is you’re making in combination with your own creative vision. Some items can have a wider binding; 3" would be a wide binding. Remember, width is traditionally considered to be what you "see" from the edge on one side – not the width of binding from front to back where it wraps around the raw edge. Other projects call for a narrow binding: ½" is a pretty narrow binding. For our quilt example, we’ve decided we want to "see" a ½" binding. But, before you can figure out the cut width of the bias strips, you have to think about the what type of bias binding you're going to use: single fold or double fold. Let’s take a moment to look at the differences and the math (yay! math!!)
Single fold vs. double fold
If you’ve seen single fold bias binding and double fold bias binding, you may be under the impression that the only difference between these two is how the strip of fabric is pressed. Well, it’s a little more than that.
Single fold bias binding (shown on the left above) is ideal for projects that will not be seeing a lot of use, such as a wallhanging. It takes less fabric to make, and is easier to handle under the needle since it’s only one layer of fabric. To determine the width of single fold bias binding, multiply the determined width (½" in our example) by 4. So, ½" x 4 = 2".
NOTE: Some quilters choose to subtract ⅛" from their final cut width measurement to allow for the gap between the raw edges of the binding when it’s pressed. We’ll leave it up to you to decide if you want to subtract this from your strip width.
Double fold bias binding (shown on the right above) is perfect for items that will be washed or worn often. It’s stronger because it’s a double layer of fabric. You can probably guess it also requires more fabric. To determine the width of double fold bias binding, you have to multiply the determined width by 6. So, for our example, if we choose to use double fold bias binding, our equation is: ½" x 6 = 3".
For the continuation of our mythical quilt example, we’re going to use ½" single fold bias binding.
Luckily, the quilting community has come up with a handy formula to make it easy to figure out how much fabric to buy. Deep breath... this may bring back some bad memories from 4th grade math class.
NOTE: If you're a S4H regular, you may notice, in previous tutorials, we’ve provided you with other approaches to figuring out how much yardage to buy. As with most techniques in sewing, there’s always more than one way to do things. You really have to try each one to find what works best for you We always do a lot of research on our subjects, then combine this with our own sewing experience, in order to provide you with what we feel is the best information. For this tutorial, we decided to share yet another way of calculating fabric yardage.
Quilters refer to this as the "Magical Math Formula!" Here we go…
Multiply the total inches of bias binding you need by the determined cut width. For us, that means 156” x 2” = 312”.
Use a calculator to determine the square root (there are also square root tables online). The square root of 312 is 17.66352. Round up to the next whole number: 18.
This tells us we need to start with an 18" x 18" square in order to cut enough bias strips to go around our 36” x 36” quilt.
Add an additional 2” to 3” for seaming the strips. 18" + 3" = 21". We need a 21" x 21" square of fabric.
NOTE: You can use a rectangle to make bias binding, but we like to use a square because it keeps things nice and simple, and we know Sew4Home visitors like it simple!
Divide 21" by 36" (the inches in a yard) to figure out the total yards needed. 21 ÷ 36 = 0.5833 yards, just a bit more than a ½ yard. The next common cut measurement is ¾ of a yard, which is 27". If you want to be more precise, some retailers will allow eighth cuts. In this case, ⅝ yard is 22½" - just enough.
If calculating yardage on your own seems overwhelming, there are charts available online (search "calculate bias binding"), in books, and as laminated cards. These helpful cheat-sheets quickly tell you how much yardage you need to make bias binding of various widths and lengths. Since our quilt example is on the small side, we do not need more than 1 yard of fabric. Most likely, the majority of projects you make will require ½ to 1 yard of fabric for the bias strips. Of course, if you’re following a pattern, you should be provided with the size, type, and length required.
NOTE: We recommend keeping a pocket size reference chart of formulas handy near your computer and/or in your purse. You never know when you'll need to buy fabric on the fly.
Before we go onto the next section, we want to mention that before you actually cut your square, you may want to preshrink or prewash your piece of fabric.
Tools you’ll want/need
You probably have a few of the items listed below already. Some are more vital than others to accurately cut and sew bias binding. But as we always say, working with the proper tools makes everything go faster, feel easier and look better when it's done.
Rotary cutter(or sharp fabric scissors)
Cutting mat – A must have for rotary cutting, preferably one with angle markings.
See-through quilt ruler – Again, preferably with angle markings, and approximately 24" long.
Bias tape maker – These come in a variety of sizes. They’re specifically used as a pressing tool for single fold bias tape. You can learn more about them in our product review.
Depending on your sewing space, a Clover Mini Iron may be a great tool for you when it's time to press your binding.
Automatic bias tape maker – If you are going to be making yards and yards and yards of bias tape, you may want to consider one of the products we love: the Simplicity Automatic Bias Tape Maker. We did a review of this great machine and use it often in the S4H studios.
Depending on the make and model of your sewing machine, you can also ask your sewing machine retailer about feet designed specifically for attaching binding. Keep in mind; these usually have predetermined widths that can be fed through the foot itself. To learn more, take a look at our tutorials on sewing trims with specialty feet and the Rotary Even foot from our exclusive sewing machine sponsor, Janome.
You can use your standard sewing machine foot for piecing the strips together end to end.
Making the bias binding
The first step is to cut the bias strips. If you've been following along, you know in our example, we need to cut 2" bias strips.
NOTE: Similar to our note above about determining yardage, here we share with you another approach to cutting and sewing bias binding. It's slightly different than what we’ve shown in previous tutorials. We chose to show this particular technique because we think it’s easy to understand and it keeps the cutting very compact. We also selected a striped fabric so you can clearly see the result of the bias cutting.
Using your preferred method, cut the proper size square. Ours is 21" x 21".
Lay your fabric square flat on your work surface, right side up.
Note: We lay the fabric right side up because we will be drawing lines on the fabric for cutting. We find marking the wrong side is better for visibility. Plus, if we make any marking errors, at least it’s on the wrong side!
Take the bottom right corner and bring it up to meet the upper left corner to create a triangle. The folded edge is the "true bias" angle.
Now, take the lower left point of the triangle and bring it up to meet the upper right point of the triangle.
You will now have a second fold at the left and should still have a triangle in front of you.
NOTE: If you’re using a cutting mat, you can use the grid to help keep your fabric edges straight during the folding process.
With a ruler and marking pen or pencil, draw a line half the width of your desired cut strip from the 2nd folded edge of the triangle (the left closed fold - not the right open fold).
Using our example, this meant we marked a line 1" from the left folded edge.
Mark a second line from the first marked line the exact width of your desired cut strip. We marked a line 2" from the first line.
Continue in this manner, marking at the exact width, until you have completed marking across the entire triangle.
Cut along each marked line, using a rotary cutter and ruler, or a sharp fabric scissor.
Except for the very first cut at the fold, you will now have two layers of bias cut binding for each cut width.
Since you’ve cut your fabric on the bias, you will also notice all the strips have angled ends – perfect for piecing the strips together!
Again, the only exception will be the very first strip you cut at the fold. Using a ruler, preferably one with a 45° angle mark, mark and cut each end of this strip to match the others.
Take your pile of newly cut bias strips to your sewing machine.
NOTE: Handle your bias strips with care, they can easily stretch out of shape!
Place two strips right sides together, criss-crossing the angled ends. Little "points" will extend slightly beyond each long straight edge. This is correct. Secure in place with a pin if needed.
Using a straight stitch, and ¼" seam allowance, sew the strips together.
NOTE: If you have a ¼” Seam foot for your sewing machine, now is a great time to use it!
Trim off the little "points" with a rotary cutter or scissors.
Continue to sew all the strips together in the same manner.
Press all the seams open.
Using a bias tape maker and your iron, press the single fold bias tape as you gently guide it through the bias tape maker.
NOTE: A bias tape maker (a manual oneor the Simplicity Automatic one) is great aid in forming the single fold tape. It’s like having a third hand. You don’t have to use one, but we recommend it to make the job easier.
To fold the tape with only an iron, first fold your strip in half lengthwise, wrong sides together and press.
Open up your strip wrong side towards you, so you can see the center crease.
Fold each side towards the center crease and press.
NOTE: Here's a favorite trick picked up from the bias tape you buy pre-made in the packages: fold one side nearly all the way to the center fold mark – so it is almost touching the fold; fold the other side just a little short of the fold line. So you end up with one fold that is slightly narrower that the other, BECAUSE that way when you stitch it on, you stitch the narrow side down first and then when you flip it over to do the final topstitching, you will be assured of catching the wider fold in your seam line.
Fold again along your first crease, right sides together, so your two folded edges are together. Press again to set the center crease.
Ta-da! You’ve made beautiful bias tape. Now you can sew it to your project.
NOTE: When we created our bias tape for this tutorial, we used all the bias strips cut from our triangle. Once sewn together, we actually had 210" of bias tape, way more than we needed. In most cases, you can usually skip sewing the last short cuts of bias strips into the final length. Or, use them mixed in between the longer strips so you do not have as many seams toward the end of your bias tape. Remember, any excess bias tape can certainly be used on a smaller project.
Attaching bias binding to a curved edge
Since bias binding is ideal for finishing a curved edge, we will be showing you examples of that here.
For detailed instruction on sewing binding to a straight edge, turning corners, and finishing the ends once you’ve sewn completely around the edges, please review out tutorial: Complete Step by Step for Binding Quilts & Throws. You will notice we only used straight-grain binding in that tutorial, but the application for sewing binding is exactly the same.
NOTE: Just a reminder, our example below uses single fold bias binding. The sewing steps are similar for double fold, except with double fold, you do not open the folded edge to begin sewing, you simply leave it doubled.
Open one side of the pressed edge of the single fold bias tape. If you used a bias tape maker or followed our note above, you are unfolding the slightly narrower side.
Leaving a tail at the beginning, line up the raw edge of the bias tape with the raw curved edge. Your bias tape and your fabric should be right sides together. Secure in place with a couple of pins to get started.
NOTE: For detailed instructions on how to begin sewing binding, be sure to read the above referenced tutorial.
Using a straight stitch and a ½" seam allowance, sew the bias binding to the raw edge, using the crease line as your stitching guide.
Sew slowly, and continue to guide and shape the bias binding along the curved edge. You will need to watch the edge closely, stop often, and slightly pivot the fabric. If you have a sewing machine with a knee lifter, this is a great time to use it!
Wrap the unsewn folded edge over the raw edge of the fabric to the back. Secure in place with pins on the right side – in the "ditch" of the seam you just sewed.
NOTE: It's a good idea to press the binding along the edge before wrapping it around to the back.
NOTE: At this point, you will need to address how you plan to finish the ends, with a simple overlap, or by sewing the ends together. We’ve provided details on how to do both in our tutorial: Complete Step by Step for Binding Quilts & Throws.
Stitch along the bias binding, just next to the original seam, on the right side. Most people choose a straight stitch and thread that matches the binding for this step, but you can also use a decorative stitch with contrasting thread for an added effect. (We used contrasting thread so you could see our stitching clearly!)
When you flip over to the back, you'll see that you've perfectly caught the entire length of that ever-so-slightly wider fold on the back. Yay!
Tips we’ve picked up along the way
True bias is cut at 45°, however fabric cut on any angle is considered bias too. The difference? The degree of stretchiness.
We mentioned in this tutorial that we used another approach to cutting the bias strips. Believe it or not, there are still more to try! If you do a general Internet search, you’ll find lots, just be cautious as some can be a bit of a brainteaser (unlike our super simple, easy-to-follow tutorials here at Sew4Home!).
As you become addicted to making bias binding, you’ll find you almost always have some short little strips left over. Place these in a box or basket for future projects. You can piece them together for a great scrappy look!
Speaking of scraps, you can also piece straight grain cut strips (or leftover pieces from a Jelly Roll) to create new fabric.
Cut your new fabric on a 45° angle, and you’ll have another beautifully unique type of pieced bias binding.
If you do not have a bias tape maker, you can create a DIY version with a pin and a seam gauge. We found some other examples of DIY bias tape makers using a craft cutting blade and a hair straightener, as well as a printable paper one! If you’re interested in seeing any of these, a general Internet search will be your friend.
If you decided to give pre-made bias tape a try, review our Cheat Sheet.
Sample Creation and Instructional Outline: Jodi Kelly