Hi! I'm presently using up my stash creating 12 inch blocks for a "full size" bed quilt, not following any particular pattern and not sure how many blocks I will need. I was going to lay the blocks across the bed as I create them to see how many I will need. I would like to know how to calculate the amount of fabric I will need for a solid back. Also, I would like to place one inch sashing in between the blocks and add a 2 or 3 inch border around the quilt (could be same color as sashing). Is there a special formula for calculating yardage for that as well?
Thanking you all in advance! Pat

Someone had a question about lap quilt size and another person posted a response showing the sizes of bed quilts. If you look at that and add a few inches (to be safe) all the way around. You should do okay. Most fabric is 44 or 45 inches. You will probably have a seam, but most backs do unless you go with really wide fabric such as 60 or 90 inches. This may help you a little, but I am sure someone more experienced than me can give you an even better answer.

I use the "lay them on the bed to see if I have enough blocks" method, also.
If you have a design wall/board, that is helpful, too.

If you take photos of the different layouts, and then look at them later, I've found that's helpful, also. I see things in the photo that I missed, before.

There are so many variables to the answer:
How big is the bed?
How much of a drop do you want?
Do you want it to go over or under your pillows?
How much fabric do you have available?
How do my blocks look the way they've been laid out?
Some settings seem to look better with an even number of blocks, some seem to look better with an odd number.

Thank you for your suggestions. I just started making 12inch blocks Friday evening. I already have 10 made. When 12 are completed I will lay them out on a bed for further study. -Pat