Calculating yardage for backing??
 

How do you calculate it? I need to buy backing for a twin size quilt but have no idea how much to buy. I'm always scared I won't get enough.

What are the measurements? If it is 39 x 75 you need 2 yards and 3 inches without adding anything extra. The 45" width will be wide enough to cover the 39 part and the length will be covered with the yardage. I would add 5 inches longer just to be sure you have enough. Hope that helps.

If your quilt is also big enough for a drop on each side of the mattress, your quilt might be sized a bit bigger. So let's add 10" to each side of the twin mattress size of 39 x 75 for the drop. (I'm making this up - no idea what your quilt size really is!) So your quilt might be 59 x 75. Because the width of the quilt is wider than the usual 42 - 44" quilting fabric, you need to piece the back.

I would purchase at least 85" x 2 = 170" length needed (4.72 yards). Cut the yardage in half (at 85"). Then on one piece, cut 2 strips 9" wide (9" x 85"). Trim selveges. Sew the narrow strips to each side of the 85" full width piece. Now you have a back that is 42" + 9" + 9" = 60" x 85"

A few more ideas:
http://www.allpeoplequilt.com/techni...backs_ss1.html


John Flynn's diagonal pieced back instructions (scroll down the page)
http://www.flynnquilt.com/workshop/FreeLessons/

I draw a rectangle the size of the quilt top and write the measurements on the end and sides. It is best to have a seam going horizontally across the back of the quilt. If your quilt is 59 x 72 and the fabric is 44 inches wide,you would need two pieces 2 yards long, sewn together would be 83, the seam taken off. Subtract the 59 from the 83, which leaves 24 inches, cut off 12 from each side so the seam is in the middle of your quilt. For this you would need 4 yards of 44 inch fabric.
Years ago I was told by my mother you need 5 yards of 36 inch fabric to do a double sized quilt so if you see a good buy on fabric you would use someday for a backing, get 5 yards or a bit more if it is the end of the bolt. Today you won't find 36 inch fabric, you might find 54 or 60 inch wide. And you have extra for your stash.
I like to use the 1/4 inch graph paper to decide fabric needs, each square to represent a foot or a yard, depending on the project and needs. 11 squares would equal the 44 inch fabric we buy today, this is a good way to estimate your needs.

Maybe this will help.

what size is your finished quilt. Cant give accurate information unless one knows the dimensions.
Twin can be most any size.

as a long arm quilter, i prefer a seam from side to side, and not up and down, and i like my backing seams deep, at least 1 inch, and press the seam open. when i get fabric for backing, i add up to 6 inches on both sides, you dont want to be short, so if your quilt is 70 wide 82 inches is what i would get, and you have to add that twice, and if your quilt is longer than 88, you have to add it 3x....for a total of 246 inches =alsew, 2 seams in the back, so a total of 7 yards would be enough.
good luck
katz