It is possible to shorten a floor-length dress. Transform a long dress into a knee-length or mini version. Avoid embarrassing stumbles by keeping a long dress off the ground. If you have any experience with a needle and thread, you'll have no problem shortening a dress. All you need are an adequate working area, a friend for a few minutes, and basic sewing supplies.
Try the Dress On
Try the dress on. Stand in front of a floor-length mirror and place a finger where you want the hem of the dress to end. Use a straight pin to mark where you want the hem to end. Or, if you want to keep it floor length, but it's a bit too long, have a friend pin up the dress to the correct length.
Make Your Marks
Turn your dress inside out. Measure and mark 1 inch down from the pin at the desired length. This 1 inch is the hem allowance. Then measure upward from the bottom of the dress to the mark to calculate how much you'll have to cut off. Using this measurement, mark again, this time all the way around the dress, to create your cutting line. A pencil or piece of chalk will work best for marking. Avoid dark black or permanent markers. You can find tailor's chalk at most fabric or craft stores.
Cut Off Excess Fabric
Use a pair of sharp fabric scissors to cut along your cutting line. It's important that the line is straight. If it's crooked, your hem will be crooked. Before you cut, you may want to pin the the skirt of your dress together, close to where you'll be cutting. This technique prevents your dress from slipping around while you're working.
Sew the Hem
Fold the bottom edge of the dress up 1/4 inch and pin in place. Use a sewing machine to stitch. Remove the pins. Turn up the bottom of the dress 3/4 inch and pin in place. Use a needle and thread or a sewing machine to sew the edge of the hem to the dress. If stitching by hand, use a catch stitch to create a flexible hem with some give. Remove the pins.
Press the Hem
Press the new hem, checking the heat setting before touching the iron to the fabric. If your iron is too hot, it can melt your dress. A lower heat setting is normally the best bet if you don't know what kind of fabric your dress is made of. Turn your dress right side out and enjoy!