Crop tops were popular during the early '90s and have begun becoming popular once again with the grunge fashion resurgence. Crop tops are short shirts that fit high above the waist and can be worn with low trousers, exposing the midriff, or with high waist trousers for a more modest look. Making the perfect crop top can be done cheaply and easily using old T-shirts that you already love. Making a crop top at home guarantees that the shirt will be the length you want it to be.
Select an old shirt that fits you well in the shoulders and chest. Because crop tops flare out and can be boxy at the bottom, the most flattering crop tops fight snugly at the top in the shoulders, chest and arms. The shirt can be a T-shirt or tank top made of any slightly stretchy material.
Put the shirt on and mark where you want the crop top to fall on your body. Most crop tops fall slightly below the edge of the ribcage, just above your navel and hip bones, but you can make the shirt longer or shorter depending on how "cropped" you want the look to be.
Take the shirt off, turn it inside out and place it on a flat, clean surface. Align the ruler with the mark you made on the shirt and trace a straight line across the front of the shirt. If you plan on hemming the shirt, make your line 1/4 inch below the mark. Cut as straightly as possible across the line on the T-shirt. Be sure to cut through both the front and back of the shirt.
Leave the shirt frayed at the edges for a more "grunge" DIY look, or pin and sew a 1/4-inch seam across the front and back of the T-shirt for a more finished look.