There's nothing more unattractive than wearing clothing that's too small. Though sweatshirts come in typical sizes, their necklines are often constricting and uncomfortable. Instead of banning a beloved shirt to the charity bin, exploring do-it-yourself tailoring can allow you to get a little more breathing room without spending a lot of cash.
Flatten the sweatshirt backside-down on a clean, dry surface. Straighten the hood so the edges lie squarely. Place the cardboard between the front of the shirt and the back.
Locate the center of the neckline, where the edges of the hood are sewn in. Measure between two and five inches down the center front, depending on how deep you want the V of the shirt. Place a straight pin horizontally in the fabric to mark this spot.
Sketch a straight line down from the center of the neckline to the pin. Use the tape measure as a straight edge to ensure the line is not crooked as it serves as the cutting guideline.
Cut the seams of the hood where the edges are sewn into the shirt. The cuts should be roughly 1/2 inch long, just enough to separate the edges of the hood from the neckline.
Cut down the line on the front of the shirt, stopping at the straight pin.
Remove the straight pin and the cardboard from the shirt. Turn the shirt inside out and place it back on the flat surface with the newly cut V facing out.
Measure 1/8 inch from one of the cut edges in the direction away from the V. Turn this small section of fabric toward the nearest arm, and place straight pins to hold the fold in place. Repeat with the other cut edge.
Sew the pinned sections of fabric in place, removing the pins as you stitch. Turn the sweatshirt so it is right-side out once more.
Double-check the sketched line to avoid cutting a crooked V. Leave the raw edges of fabric exposed if you aren't confident in your sewing skills. Iron-on hemming tape is another option for holding edges in place.
Pay close attention while cutting; cutting too much could leave you with ragged edges instead of a neat, tailored look.