I tend to make mine 3-4" wider than the top.

Narrow strips of batting can be very handy to use when making a tote bag/purse. It's much easier to handle to trim down than hauling out the roll or package of batting again. :)

Go ahead and leave just a little overhang. The best teacher is experience. I now know why I leave at least 4 inches overhang.

I make my backings about 2" larger all the way around - just in case. I use to leave more but, found I really didn't use that much more. When pinning my quilt sandwich together I pin at the very edge so there is no way it can stretch or move anywhere and it makes it easier and more accurate when I cut it to size for the binding to be attached. I quilt within about 1/4 - 1/2" from the pins and that makes it easier for me to hand stitch the binding to the backing. I use to flip the back over the front and sew that down for the binding, I stopped that.

I only have about 1-2 inches more .... just so I can make sure that all of the quilt top has a matching size back. Sometimes I fold the 1 inch overhanging backing over the top and do a quick huge basting stitch... to keep all my outer edges protected and they don't ravel as much. It's quick and easy to pull out when you get near the outer boarders. :mrgreen:

If you're going to send your quilt top out to be quilted, a longarm quilter would like at least 5 inches, preferably 10 inches larger backing and batting than the top. We have to use clamps and we need the extra yardage to attach to the leaders. After it's all quilted, it's nice to have some extra when you trim. It makes for a much straighter edge.

Cynthia

One of my students cut her back to small and didn't have any more material. She wanted to quilt it anyhow. I always trim the quilts for them. I had to cut 3" from her border to square up the quilt. I hated to cut throught that beautiful border. She is 93 and still quilting so I do what ever she wants. She told me she has to machine quilt now bc she is running out of time. She is a precious lady.

For reasons others have listed, I, too, make my batting and backing larger than the top. However, I save the batting carefully and in a specific box to keep batting together. Recently, I made four baby quilts using this method. I had enough batting left to use for the fifth baby quilt. Just overlap it a smidgen so there will not be a space between the pieces of batting. Silvia