Im on my second quilt ever,, the first was a baby quilt and with your help it turned out great! Now I am tackling a T shirt Quilt for my daughter made from her college tshirts
I have 6 rows of 6 11x14 squares . Or final measurements ( without border) is 84x66 . I need to know how many yards of material I need for the backing? Can you help?

You have to know the total size of the quilt top, including the borders, before you can calculate backing yardage. Provide that and I am certain you'll get a quick answer.

You will need a minimum of 5 yards. This will be pieced vertically and will give you appox 90 inches in length, if it were me I'd get 5.5 yards.

To figure backing I always figure the smallest side first (66 inches) figures 2 yards = 72 X 88 which would not be long enough for the length 84 inches, so then I turn it around - 84 divided by 36 = 2.33 yards x 2 = 4.66 which will measure overall 88 x 84, now you have enough width, but if you are sending to a longarmer they are going to want more length, hence I rounded up to 2.5 yards x 2 = 5 yards (now measures 84 x 90).

Clear as mud right?

I agree with Leslie --- 5 yards should be pretty close, but you may want to add another 1/4 just to be safe in case it isn't cut straight at the store. Also, you didn't mention if you are going to prewash the back --- you may need to allow for shrinkage, too.

If you used the measurements above (without adding any borders!) your backing would need to be 92 x 74 for a longarm quilter to it. That's what I ask folks to bring when I do their quilts. So, if you take two pieces (WOF) and seam them, they would each need to be 92 inches long. It may be easier for you to have the pieces cut right at the fabric store where they have the nice big tables! Then just join the pieces (on the long side), and you are done. Of course, if you add borders, that will change everything above! :wink: