If you avoid garments that require buttonholes because you think they’re scary, fear no more. Making an in-seam buttonhole is easy peasy, and a great way to showcase a special button, like on a jacket front. As its name suggests, it’s simply an opening in the seam to accommodate a button closure.
Some patterns come with instructions for in-seam buttonholes. Garments with add-on front bands like shirts, are a natural for this feature. Other times, it’s a design touch you’ll need to add yourself. To do so, figure the button location, then draw a line on the pattern where you need the button(s) to be—normally at the center front line. Note that the opening can be vertical or horizontal, depending on the garment. Cut the pattern on the drawn line, then add a 5/8” seam allowance to each side of the cut to create a seam allowance.
When you sew the seam, simply leave an opening for the button. The opening should be the diameter plus thickness of the button, plus 1/8” (.32cm) ease.
It’s a good idea to reinforce the opening with fusible interfacing on the underside of the fabric to help prevent stretching.
Mark each end of the buttonhole with a dot. Sew the seam right sides together, leaving the opening, and backstitch at the beginning and end of the slit. Press the seam allowance open, and you’ve just created a buttonhole! For a more tailored look, topstitch the seam allowance on each side.
To finish the underside, leave an opening in the facing seam in a corresponding location, then whipstitch the pressed open edges together. If the facing doesn’t have a seam (or you chose not to make one), push pins through the end of the buttonhole to mark the placement.
Carefully cut a slit and turn under the cut edges, hand stitching to the buttonhole seam allowances.