How to sew buttonholes and buttons

To sew a buttonhole, interface the area, mark the buttonhole's position and length, sew it with your machine's buttonhole foot, then cut it open between the ends with a pin across each end as a stop. Make each buttonhole as long as the button's diameter plus its thickness, which for a flat button is about 3 mm (1/8 in) longer than the button. Sew the button on with a thread shank so it sits on top of the buttonhole layer without pulling it tight.

How long should a buttonhole be?

Measure the button across and add its thickness. A flat 1 cm (3/8 in) shirt button needs a buttonhole of about 1.3 cm (1/2 in); a domed or ball button needs more, because it has to pass through at its thickest point. For an unusual button, wrap a narrow strip of paper around it at its thickest point, pinch where the paper meets, and halve that length: that is the shortest opening the button can pass through.

Always sew one test buttonhole on a scrap with the same layers and interfacing as the garment, cut it open and push the button through before you touch the real thing.

Where do buttonholes go?

• Vertical buttonholes run along a button band or placket, centered on the center front line. They let the button shift a little up and down, which suits shirts and blouses.
• Horizontal buttonholes take strain sideways, so they suit waistbands, cuffs and close-fitting fronts. Start them 3 mm (1/8 in) beyond the center front toward the edge, so that when the garment pulls, the button sits exactly on the center front.
• Which side: by convention, women's garments have the buttonholes on the right front and men's on the left front.
• Spacing: place the top buttonhole about 1.5 cm (5/8 in) below the finished neckline and the lowest at least 6 cm (2 3/8 in) above the hem, then space the others evenly, usually 7 to 10 cm (2 3/4 to 4 in) apart. Put one at the fullest part of the bust to stop the front gaping. The button spacing calculator does the arithmetic.

If your pattern marks the buttonholes, as the button-front version of Sewly's woven top does, use the marks and check their length against the buttons you actually bought.

Prepare: interfacing and marking

1. Interface the button band and the buttonhole area with a light or medium fusible interfacing. Without it the buttonhole stretches and the stitches tunnel. A cut-on button band is interfaced on its facing half.
2. Mark each buttonhole on the right side with a water-soluble pen or chalk: a line for the length and a short cross line at each end.
3. Sew your test buttonhole on a scrap prepared exactly like the band.

How to sew a one-step buttonhole

Most modern machines sew a one-step, or automatic, buttonhole: the foot measures the button and the machine sews the whole buttonhole without stopping. If you are still getting to know your machine, sewing machine basics covers threading and tension first.

1. Snap on the buttonhole presser foot and put the button in the slide at its back; the foot sets the length from it.
2. Select the buttonhole stitch and, on most machines, pull down the buttonhole lever so it sits behind the tab on the foot.
3. Place the fabric under the foot with the needle at the start of your mark. Check your manual for the direction your machine sews, because it varies.
4. Hold the thread tails and press the pedal steadily. The machine sews one side, a bartack across the end, the other side and the closing bartack, then stops.
5. Pull the threads to the wrong side and knot them. On fabric that frays, dab a little seam sealant on the cutting line and let it dry.

How to sew a four-step buttonhole

Older and simpler machines split the buttonhole into four dial positions: a bartack, one side, the second bartack and the other side.

1. Mark both ends clearly: the machine will not stop by itself.
2. Set step 1 and sew five or six stitches for the first bartack.
3. Set step 2 and sew down one side to the end mark, counting the stitches.
4. Set step 3 and sew the second bartack.
5. Set step 4 and sew back up the other side with the same number of stitches, so both sides are the same length.

Cutting the buttonhole open

Push a pin across each end of the buttonhole, immediately inside the bartacks. Insert the point of a seam ripper at one end and cut toward the middle, then do the same from the other end; the pins stop the blade before it slices through a bartack. A buttonhole chisel pressed down onto a wooden block gives an even cleaner cut. Trim any stray threads with small scissors.

How to sew on a button by hand

1. Close the garment, matching the center fronts, and push a pin through each buttonhole to mark the button: at the outer end of a horizontal buttonhole, 3 mm (1/8 in) below the top end of a vertical one.
2. Thread a hand needle with a double strand of all-purpose thread about 60 cm (24 in) long, knot it, and take a small stitch at the mark on the right side, where the button will hide it.
3. Lay a toothpick or a thick pin across the top of the button, between the holes. It holds the button away from the fabric to leave room for the shank.
4. Stitch up and down through the holes six to eight times, over the toothpick. On a four-hole button, make two parallel bars or a cross.
5. Remove the toothpick, lift the button, and wind the thread five or six times round the stitches under it to form a firm shank.
6. Take the needle to the wrong side and finish with three small stitches on top of each other.

Buttons with a loop underneath, called shank buttons, already have their space and need no thread shank. Many machines can also sew flat buttons: lower the feed dogs, set a zigzag as wide as the distance between the holes (often 3 to 3.5 mm), turn the handwheel by hand once to check that the needle clears both holes, then sew about eight stitches.

Common buttonhole problems and fixes

• The button will not go through. The buttonhole is too short for a thick or domed button. Sew a new one 2 to 3 mm (1/8 in) longer, and test on a scrap next time.
• The fabric jams at the start. The foot is tilted by a seam or a thick edge. Start on a flat area, or slip a folded scrap under the back of the foot to level it.
• Thin fabric puckers or tunnels. It needs support. Add interfacing, or sew over a layer of tear-away stabilizer or tissue paper and tear it off afterwards.
• One side is denser than the other. On a four-step machine, count the stitches; on any machine, let the feed dogs move the fabric instead of pushing or holding it.
• You cut through a bartack. Secure it with a few hand stitches and a drop of seam sealant, and always use pins as stops.
• The front gapes between buttons. A button is missing at the fullest part of the bust. Add one there, or a small snap.