If you don’t have a tank top to use as a template, don’t worry. You can still make a tank top.
If you don’t have a tank top to use as a guide, cut the sleeves and collar off of your t-shirt. Consider folding the shirt in half before cutting it, so that both sides will be even.
If you’d like the edges to be raw and un-hemmed, you can skip this step. T-shirts are made from jersey material, which does not fray.
If you are using a sewing machine, try to use a stitch intended for knit fabrics. It looks like a straight stitch, except that it is broken up by a V every few stitches. When you are done sewing, remember to tie the ends of the threads off into tight knots, and to snip the excess tail ends off.
A racerback tank top has wider armholes in the back, leaving a skinny band of fabric between the shoulder blades.
Make sure that you cut the same amount from each side of the shirt. Cut the armholes deep. They should be a few inches apart when you are done.
Do not cut the front of the shirt; you are only cutting the back. Racerbacks have a plain collar in the front. If you prefer a plain racerback, you can skip this step, and wear your racerback. The next few steps will teach you how to make a fancier racerback.
