A single shirt button might be a tiny thing and just one of many, but if it pops off and isn’t replaced, the shirt will likely become unwearable. Don’t discard an entire garment for lack of a single button. Securely sewing the original button, a spare or the closest match you can find back onto the shirt is an important skill. It’s a simple, easy-to-learn task, but using the correct technique -- which involves creating a thread shank under the button -- is key to ensuring a smooth fit when the shirt is buttoned up.
Button up the remaining buttons on the shirt and lay the shirt out flat on a work surface so that the plackets -- the vertical strips of fabric with the buttons and the buttonholes along them -- are smooth and aligned.
Poke a straight pin through the center of the buttonhole with the missing button, into the button placket. This marks the spot where the missing button should be. Alternatively, make a mark on the button placket through the center of the buttonhole using a fabric marker.
Unbutton the shirt and carefully lift the buttonhole over the pin. Make sure the pin stays in place to mark the spot where you need to sew the button.
Take an arm’s length of all-purpose thread that matches the color of the thread used for the other buttons. Fold the thread in half. Thread the looped end of the doubled thread through the eye of a needle. Knot the other end of the doubled thread.
Place the button on the button placket over the spot marked by the pin or marker. Remove the pin. Align the button so that its holes are parallel to the buttonhole.
Poke the needle from the underside of the button placket and up through one of the button’s holes. Pull the thread taut.
Insert the needle through a second hole, poking it down through the fabric layers and pulling it taut on the underside of the button placket.
Slide a toothpick or matchstick between the top of the button and the threads. Pull the needle gently to tighten the stitches over the toothpick or matchstick. This step creates just enough room between the button and the placket to create a thread shank.
Continue stitching up and down through the button’s holes, taking the thread over the toothpick or matchstick. With a two-hole button, simply alternate stitches between the two holes. With a four-hole button, examine the other buttons on the shirt and replicate the stitch pattern with which they are attached. This is commonly in the form of an “X” or a square box shape. Three or four stitches through each pair of holes will be sufficient.
Bring the needle from the underside to the upper side of the button placket, without taking it through any of the button’s holes, and pull it taut underneath the button. Remove the toothpick or matchstick.
Lift the button up from the fabric and wind the thread around the stitches underneath it two or three times. This forms a thread shank, which holds the button just above the placket.
Make a secure knot as part of the final wrap-around of thread, or sew two or three tiny stitches underneath the button to secure the thread. Snip the thread close to the knot or tiny stitches so that the ends are concealed underneath the button.
If the button only fell off the shirt recently, you might still be able to detect the needle holes from the original stitching. There might even be some threads left in the fabric. If this is the case, you don’t need to mark the spot with a pin or marker. Just remove any stray threads and sew the new button over the original stitching holes.
Some sewing machines have a button sewing function, which requires a special button foot. Follow the instructions in the manual for your machine if you want to sew the button on by machine instead of by hand.
If you lost the original button, don’t have a spare and can’t find a close enough match, consider replacing all the buttons on the shirt with a new, matching set. This will take some time, but if you’re a perfectionist and can’t stand the look of a single ill-matched button, it might be the best option. Changing the buttons to those of a different style or color can also transform the look of the shirt and make it unique.