Please help me with my math
 

I'm getting ready to order fabric for sashing my first large project and I want to make sure I have enough. Can you please check my math?

I'm making 80 4" squares, and I want 2.5" sashing around each block. I'll be using cornerstones, too.

So I figure 4 sides x 80 squares = 320 4" strips = 1280" of strips

1 yard of fabric = 560" of 2.5" strips

1280/560 = 2.3

So 3 yards is WAY more than enough, right?

Oh, and I figure for 8 x 10 rows I'll need 90 cornerstones.

Thanks for helping. I really want to get this right the first time!

Are you putting sashing on the edges? Or will you have a border?
Usually you add sashing to the right and bottom of each block.
Then add to the top and sides if that's what you want or put a
border all around. If you add sashing on all four sides you will
end up with double sashing. Here's a link to help you. Draw it
on graph paper then count how many sashings you need.
http://www.synthcom.com/~val/Quilts/...ngSashing.html

EasyPeezy has given you good advice - you won't put sashing around 4 sides of each block. Nothing is what it seems!!

Are you putting sashing on the edges? Or will you have a border?
Usually you add sashing to the right and bottom of each block.
Then add to the top and sides if that's what you want or put a
border all around. If you add sashing on all four sides you will
end up with double sashing. Here's a link to help you. Draw it
on graph paper then count how many sashings you need.
http://www.synthcom.com/~val/Quilts/...ngSashing.html

You might want to arrange your blocks before you add your sashing
because some will need sashing just on some sides and not all around.

See? I knew I needed help! Back to the graph paper!

ok, now I got 90 strips for l/r sides of blocks = 360"
88 strips for top/bottom of blocks = 352" total 712"

so 2 yards of fabric should be plenty. Unless I'm still wrong.

Should be just fine.:thumbup:

Thank you!

Not to throw a monkey wrench into the works, but sashing around all 4 sides of the block is exactly how I do it. That way all I have to do is sew the finished blocks into rows and match the seams at the corners. Takes the headache out of making sure the rows all line up perfectly on long rows of sashing.

Yikes! Monkey wrench! I might order extra fabric just in case. Boy, this stuff is complicated!