I need to know if there is a rule of thumb for the width of sashing in relation to the block size.
I am working on a quilt for my father. I made blocks and took them to a family reunion. Each attendee picked out a block and signed it. Now I want to assemble it and I have decided that it needs sashing and I am trying to decided how wide to make it. Any help will be appreciated.

I like 2 1/2 inch sashing - finishes at 2 inches. The blocks I've sashed have been 13 1/2", 10 1/2" and 9".

me too (2-1/2"), if it's a pretty small block (6") i'd go with 1-1/2"

i don't know where those smiley faces came from! i didn't do that. LOL

Do you have a design wall? A flannel backed table cloth will do. Hang it up, with the flannel side facing you and audition the sashing size. Hang the sashing material (un cut, folded like it comes from the bolt or opened out, width of fabric) and place the blocks on it - vary the spacing and see how it looks.

QUILTERS CHOICE! No set rule, whatever makes you feel good! Depends upon the size of the block and the block design. If it is a busy block design, I would go a wider - 2 to 3 inches. Most use 2" (finished). I have use as small as .75 finished to have the embroidery stand out (see below)

I agree. lay the sashing fabric out (uncut), then lay some blocks on the fabric and try different sizes. keep in mind this will not take into account the seam allowances, but you can get a pretty good idea from this. You can also see if the color sashing also works with your blocks.

I agree.