Learning how to use double fold bias tape is one of those sewing skills that suddenly makes your handmade projects look like they actually came from a boutique rather than a middle school home ec class. It's one of those techniques that feels a bit intimidating the first time you try it—mostly because there's a lot of folding and small-margin stitching involved—but once you get the rhythm down, you'll want to put it on everything. Whether you're finishing off a neckline, tidying up the raw edges of a potholder, or adding a pop of color to a hem, double fold bias tape is your best friend.
What makes double fold bias tape different?
Before we get into the actual sewing, it's worth a quick second to talk about what we're actually working with. You might see single fold tape at the store and wonder if you can just swap them out. You can't, at least not without some extra work. Single fold bias tape has both edges folded toward the center, but it's still flat. Double fold bias tape is basically single fold tape that has been folded in half again.
The beauty of this is that it acts like a little fabric sandwich. It's designed to wrap completely around a raw edge, encasing it so that no frayed bits are visible from either the front or the back. Because it's cut on the "bias" (the 45-degree angle of the fabric grain), it has a natural stretch. That's why it's so great for curves; it can bend and flex around an armhole or a rounded pocket without puckering like straight-grain fabric would.
Getting your materials ready
You can buy bias tape pre-packaged at any craft store, or you can make your own if you're feeling fancy and want a specific print. If you're a beginner, I honestly recommend starting with the store-bought stuff. It's usually a polyester-cotton blend that holds its shape really well, which makes it a lot easier to handle while you're still learning.
Aside from the tape, you'll want some wonder clips or very sharp pins. Personally, I'm a huge fan of clips for this because bias tape can get a little bulky, and pins sometimes distort the fabric. You'll also need an iron. Seriously, don't skip the iron. Pressing is about 70% of the battle when it comes to getting a professional finish.
The "all-in-one" sandwich method
If you're in a hurry or working on something relatively straight, you can use the sandwich method. This is the fastest way to learn how to use double fold bias tape, though it can be a little tricky to catch the back side perfectly.
- Open the tape slightly: Take your double fold tape and notice that one side is usually a tiny bit wider than the other (maybe by just a sixteenth of an inch).
- Position your fabric: Slide the raw edge of your project into the center fold of the tape. You want the wider side of the tape to be on the back of your project.
- Pin or clip: Secure the tape every inch or two. Make sure the fabric edge is shoved all the way into the fold so there are no gaps.
- Stitch it down: From the front side, sew a straight line very close to the inner edge of the tape (this is called "edgestitching"). Because the back side is slightly wider, your needle should naturally catch the back layer of the tape as you sew.
This method works great for things like blankets or straight edges, but if you're doing a curved neckline, you might want to try the two-step method for more control.
The two-step method for a perfect finish
This is the "pro" way to do it. It takes a little longer because you're sewing two separate seams, but it almost guarantees a clean result without any missed spots on the back.
Step 1: The first pass
Open up your double fold bias tape completely. Then, open up one of the side folds. Align the raw edge of the tape with the raw edge of your fabric, right sides together. You'll notice a visible crease in the tape from where it was folded—this is your "stitch line."
Slowly sew along that first crease. If you're going around a curve, don't pull the tape tight; just let it lay naturally against the edge. Once you've sewn all the way around, it's a good idea to trim any excess seam allowance from the fabric so it doesn't get in the way.
Step 2: The flip and sew
Now, fold the tape up and over the raw edge to the back side of your project. This is where the magic happens. Because you already sewed it to the front, the tape will naturally want to wrap around.
On the back side, make sure the edge of the tape covers the line of stitching you just made. Pin or clip it in place. From the front, you can "stitch in the ditch" (sewing right in the crack between the tape and the fabric) or edgestitch right on the tape itself. Since you pinned it carefully on the back, you'll catch that edge every time.
How to handle curves without losing your mind
The most common reason people look up how to use double fold bias tape is because they've hit a curve and everything has gone sideways—literally. If you find your tape is rippling or the fabric underneath is bunching, don't panic.
The trick with curves is to use your iron to "shape" the tape before you even get to the sewing machine. If you're sewing a concave curve (like a neckline), you can steam the tape into a slight curve that matches your pattern piece. This takes the tension out of the fabric.
When sewing, go slow. For tight curves, you might need to stop with the needle down, lift the presser foot, and pivot the fabric slightly every couple of stitches. It feels tedious, but it's the only way to avoid those annoying little pleats.
Dealing with the ends
Eventually, you're going to come back to where you started. You can't just overlap the ends and call it a day, or you'll end up with a bulky lump.
A simple way to finish the ends is to leave about two inches of tape hanging off at the start. When you come back around, stop sewing a few inches before the start. Fold the beginning end of the tape back by about half an inch (wrong sides together) to create a clean folded edge. Then, lay the ending piece of tape directly over it, trim the excess, and finish sewing. It creates a neat, tucked-in look that won't fray.
Troubleshooting common issues
Even if you follow every step for how to use double fold bias tape, things can still go a bit wonky. Here are a few things I've learned the hard way:
- The back side keeps slipping: If you keep missing the back edge of the tape, try using a slightly wider bias tape or stick to the two-step method. Also, check your pinning—if you pin vertically (perpendicular to the edge), it usually holds the layers together better.
- The tape looks "twisted": This usually happens if you pull the tape too hard while sewing. Remember, it's stretchy! You want to guide it, not yank it. Let the feed dogs of your machine do the work.
- Puckering on necklines: This usually means the seam allowance of the garment is too wide for the tape. Trim your seam allowance down to about 1/4 inch before you wrap the tape over. It gives the fabric more room to breathe inside the fold.
Why it's worth the effort
It might seem like a lot of steps for a simple edge finish, but once you master how to use double fold bias tape, a whole new world of sewing opens up. You can make reversible garments, unlined jackets with "Hong Kong" seams, and professional-looking home decor.
It's one of those "level up" moments in a sewing journey. It's okay if your first few attempts aren't perfect—most of us have a seam ripper nearby for a reason. Just take your time, keep your iron hot, and remember that even a slightly messy bias bound edge is usually better than a frayed one! Keep practicing, and soon you'll be able to wrap edges in your sleep.