This tutorial will teach you how to sew a curved hem with two folds, be it a concave curve (inward curve, like an elasticized neckline), or a convex curve (outward curve, like a shirt hem or circle skirt).
I also have a tutorial that shows how you can use bias tape to hem curved edges, so you can check that out here if you prefer!
By the way, this technique is for hemming woven fabric, not knit (stretchy) fabric. I have a knit tank top tutorial with a curved hem, so you can check it out here if you’re working with knit fabric.
How to sew a curved hem on a shirt or skirt – How to sew a convex curved hem
With a convex (outward) curve, the edge is wider than the part that it’s being sewn to. So, that extra fabric needs to be eased in. The more extreme the curve, the more easing is needed.
A convex curved hem is common on shirts, circle skirts, and A-line skirts. In the case of the shirt that I’m hemming, the sides are concave, so really this example is both a convex and a concave hem.
This shirt is folded by 1/4 inch twice. On a circle skirt, it’s usually the same or even smaller. And on some a-line skirts, there will be a 1/4 inch fold, and then a wider second fold, like 1 inch. But no matter what, you want that first fold to be very narrow, because it really helps to not have so much fabric to ease in.
So let’s get started on our curved shirt hem!
Sew the project together
You will want your project to be sewn together up to the point of hemming. I have this entire shirt finished except for the hem.
Sew an ease stitch along the edge
Now you are going to sew an ease stitch (sometimes called a basting or gathering stitch, but those are technically different applications). So, set your machine to the longest straight stitch and turn your needle tension down (I do tension 2, normal is 4 on my machine). With your project wrong side up, sew 1/4 inch from the edge (or whatever the width of the first fold is). Don’t backstitch, and leave 4 inch long tails at the beginning and end.
I like to work from side seam to side seam on the front, then repeat on the back, so that my sections are shorter and therefore easier to work with. On this shirt, the sides are concave, so they don’t need to be eased in. They actually need to be stretched to fit. So I cut 4 short notches in that area to help it lay flat when folded.
Fold and iron, using ease stitches as guide
Now you can iron the first fold to the wrong side, using the line of ease stitching that you just made as a guide. It’s amazing how much the ease stitching helps with this, but that’s not all it’s for!
Pull on ease stitches if needed, iron, and pin
Now for the second fold, you might need to pull on the bobbin tails (visible from right side) of the ease stitches to ease the fabric in to the curve. It really just depends on how curved your hem is. On something like a circle skirt, you probably won’t need to. But on this very curvy top, it really helped! See how it’s kind of gathered looking on the more rounded parts?
Then iron and use plenty of pins to get everything nicely in place. Take your time here. It can be a little finnicky, especially at the side seams. I like to start my ironing and pinning at center front and center back, working towards the sides. That way, if I pulled on the ease stitches too much, I can work them back out towards the sides.
Edge stitch
And now that the hard work is done, you can edge stitch! Make sure to work with the curves. It can be tempting to pull everything straight in front of the needle, but you want the curves to lay as naturally as possible. Make sure to be looking ahead, to make sure everything is still laying how it should be. You want to adjust the fabric as needed before it’s right in front of the needle, because that will be too late.
Notice how I keep all my ease stitch tails out of the fold. This makes them easier to remove in the next step.
Remove ease stitches and give a final press with iron
Use your seam ripper to cut your ease stitches in the center of the section, then pull on the tails to remove. The bobbin thread (on the outside) comes out easily, but usually the needle thread breaks off for me. But that’s ok, because it’s on the inside and won’t be seen at all.
Give it a final iron, and you’re all done! Here is the wrong side:
And the right side:
How to Sew a Concave Curved Hem
A concave (inward) curved hem has edges that are narrower than the section they’re being sewn to, so they need to be stretched slightly to fit.
This is something I would mostly do for elastic casing, like on the legs of this diaper cover I made for an Etsy order, or an elasticized neckline, etc. Or, on a shirt hem like above, where it’s just a small section that’s concave. That’s because this kind of hem just doesn’t sit that nicely, even with a good ironing. In cases where a concave hem won’t be elasticized, I would use bias binding (you can check out my post on how to do so here).
Notch curves if needed
If you’re sewing very tight concave curves, like around the side seams of a shirt, then you will want to notch into those parts. Make the notches shorter than the first fold will be. This will help everything to lay flat once you start folding.
Iron and pin the edges
Fold and iron the edges to the wrong side twice, then pin in place. Make sure you’re not pulling the fold to either side, but that it’s basically getting folded and pinned directly on top of itself. It will be a little awkward where the curves are tighter. Use more pins in the more tricky spots.
In the picture below, I actually wanted to show one side (left) without ironing, and one side (right) with ironing. The ironing definitely helps, but on something that’s not extremely curved, it’s not always necessary. Both sides of this diaper cover turned out the exact same! So it’s really a matter of personal preference.
Edge stitch
Now it’s time to finish the hem by edge stitching. Aim to stitch about 1/16 inch from the folded edge, with the wrong side facing up.
Again, you really need to work with the curves here. Don’t try to straighten them out. Let the curves lay as naturally as possible as you approach them. Always be looking ahead, to see if there are puckers that need to be redistributed before you sew them in place! This definitely takes some practice and intentionality!
All done!
And that’s it. I didn’t give this diaper cover a final ironing, seeing as it was going to be elasticized and really wouldn’t matter.
I hope you found this tutorial helpful! Have you ever attempted hemming curves, or is this your first time giving it a try? Let me know in the comments below!
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