I can see it in my mind; I just can't make it happen
 

How do I make backing out of a single piece of fabric? My quilt top is 45 x 55 and I have bought 4 yards of fabric. I know i need to cut it & sew it together somehow, but how. I have found articles on pieced backings, but can't find one or a tutorial on using a single piece of material. I made a backing one time, but I have forgotten how I did it. Please help me! I would like an answer that I can refer back to whenever the problem arises again-so I don't have to rely on my failing memory. Thanks to all who support the Quilting Board; don't know if I'd be quilting without the great help from all.

Take the finished length and add 8" to it, then cut WOF. Press the seam open & trim to finished width + 8".

There is this..
http://www.multi-patch.com/html/diag...calculator.php

Your quilt is a perfect candidate for the diagonal pieced back. Here's another helpful link: http://www.flynnquilt.com/workshop/freelessons/

There is info about halfway down the page and another link for printable instructions.

I was going to suggest a diagonal backing, too.

This is a quick and easy method from the book 'Winning Stitches' by Elsie Campbell:

1. Pre-wash and iron fabric. Fold in half across the length of the fabric, lining up the selvage edges.
2. Stitch a 1/2 inch seam along each lengthwise edge. If the selvage marks are wider than 1/2", stitch a wider seam.
3. Trim the seams to 1/4", trimming off the selvages.
4. Cut across the fold and press the side seams open.
5. Re-fold the tube of fabric so that the seams lay on top of each other, and cut along one side. Open up the backing.

Four yards = 144 inches, but you only need 126 total inches (55+4+4x2), so you could cut 1/2 yard off the 4 yd before you begin constructing the back. Keep in mind that with this method, the two side panels will be going the opposite direction of the middle panel, which would be obvious with a directional fabric.

If your quilt is going to be quilted on a longarm frame, it is better if your seam is either horizontal or diagonal. A verticals seam will cause issues for the longarmer.

Are you going to quilt it or a LA will quilt. If I pin and quilt, I add 4"or5" to the size=50"x60". I don't like to waste fabric so I would do a horizontal seam cutting 50" in length. After pinning the quilt, I would remove the excess from the bottom of the quilt. If you are having someone quilt it for you, I would ask them on the amount to add to your quilt top.

These instructions for the diagonal piecing seems much less intimidating and easy enough for me to try.
http://www.multi-patch.com/html/fabric_calc.php

Nevermind... Someone beat me to it :-)

This way is simple, no need for lots of measuring, and the LA can fit it as she likes on the frame. http://www.reddawn.net/quilt/backings.htm

I think is like the technique as Joe'smom posted but with pictures.