This simple tube top can be whipped together in a few minutes.
Measure around your bust, keeping the tape measure as tight as you will want the top to be. It will be adjustable, so don't worry about being too exact.
Mark the fabric according to the measurement you just took. Make two marks about three inches away from those marks.
Trim the fabric according to the outer set of marks.
Mark the fabric approximately five inches down from the top.
Cut in from the sides to the new set of marks, then down from those sets of marks to make the ties.
Tie tube top around your bust and trim the bottom to your desired length. You can also trim a little further in to achieve a cutout back.
If desired, you can extend the life of your top by adding a quick hem. If you choose to do a hem, trim the garment keeping in mind that it will be 2-3 inches shorter than you trim it. Fold about an inch of fabric around the top and secure it with 2 or 3 straight pins or extra needles. Do the same to the bottom. Using a needle and thread that matches your fabric, add a securing stitch every inch or so across the hem. This saves time since you don't have to sew it, therefore making it less of an investment when you decide to throw it away.
Use a ruler to draw in the cutting lines for a more precise cut.
Try to select a fabric that won't easily fray if you don't plan to hem it.
This works best with non-knit fabrics.