Things You'll Need
Instructions
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 arm̵7;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 button̵7;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 button̵7;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 ̶0;X̶1; 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 button̵7;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.