or for that matter any size. Also,When you want to design your own quilt how do you know how many 6, 10 12 etc. inch blocks make the size you want.

Divide the width of the quilt by the size of the block. That tells you how many across you need. Divide the length by the size of the block. That tells you how many for the length you need. Mulitiply the number of blocks for the width by the number for the length and that tells you how many blocks total you need.

It would depend on the pattern and whether you are using a background
fabric or not. When designing your own don't forget to add the 1/4" seam
allowance around each strip.

you do a lot of math.

if you want to figure out measurements for using 2 1/2" strips...figure they are 42" long...after trimmin the salvages you should probably figure 40"...so you want a king size quilt...110"x110"...so first 110 divided by 2" (your 2 1/2" strips give you 2" finished strips..the 1/2" is seam allowances...so you would need 55 strips to make the width...then you need 55 more to add to length making it 80" wide...then you need another set of strips...so if you wanted to just use 2 1/2" strips it looks like you need...55+55+55 or 165 strips.

see lots of math...using graph paper makes it easier sometimes to figure it all out, then you can draw it out to scale

wow! thanks, that is very helpful. I will bookmark for future quilts too. i will never remember how to do it otherwise. lol.