Book to help with quilting math?
 

I have an idea for a quilt made entirely of squares... well, almost entirely. Some of the squares will be comprised of half-square triangles. I need to know what size those triangles need to be so that when I sew them together with a 1/4-inch seam, they'll result in a 2.5-inch square to match all the other squares in the quilt. I know there has to be a relatively easy way to understand this stuff, but it's not intuitive for me at all.

I went to Amazon and searched for quilt math to see if there's a book that can help me understand how to figure out such vexing word problems. LOL (It's been a looooong time since high school math!) I didn't find anything.

Can anyone recommend a book that helps you figure out sizes when you're not following a pattern?

I don't think there is a book written specifically on that topic, although I'm sure there are several that address it as it pertains to the patterns within the book. Instead of Amazon, did you search Google? I know there are several websites that help with math, I used one recently to figure out how big to cut setting triangles.

I'm assuming you don't have a quilt design program, such as EQ?

I have Adobe Illustrator, so I can design that way, but it doesn't do the math for me the way a quilt design program would. But I don't think my computer could take one more program. It's overloaded.

*Great* suggestion on Googling the quilt math idea. Wow, I could even get help for free. Why didn't I think of that? LOL

Will this work for you? I did a Google search for "quilt math".

http://www.thecozyquiltpatch.com/LCScookbook/

For HSTs (half-square triangles), add 7/8" to the size of the finished block. You want yours to finish at 2 1/2". So you would cut your squares at 3 3/8" to start.

p.s. that page might be a good one to print out - it has lots of good info!

I don't know about books, but Quilt University has a Math for Quilters class that's next offered starting April 27th. Three lesson class for $27, taught by Dena Crain (she's great, I had her for a different class awhile ago).
http://www.quiltuniversity.com/catalog.htm
Class description is down at the bottom, under 'Other'. It's one of their most popular classes.

Victoriana Quilt Designs also offers several free PDF charts covering quilters math, including triangles of all types.
http://www.victorianaquiltdesigns.co...rts/Charts.htm

Thank you! I just found the same information here: http://www.patchwork-and-quilting.co...triangles.html

I can't believe it's so easy! LOL No wonder there's no book about it. Hard to turn that into a book

There's a book called "Taking the Math out of Patchwork." I can' find mine right now so I don't know if that's in there or not. The simple rule for HST is add 7/8ths to the size you want the finished square to be. The finished size is the size after it's sewn into the quilt. So if the plain squares are 2.5 before sewing them into a quilt and 2 inches after sewing them into a quilt you cut the squares for a same size HST 2 7/8ths. But cutting eighths is annoying so just round up to 1 inch bigger and square up the HST.

Thank you so much for the suggestions! That class seems very reasonable. I think I'll sign up.

I find it easier to make the squares (to be cut into half squares) a little larger and cut down to size.
That way you won't have to worry about the exact 1/4" seam or scant 1/4" seam. The 7/8" barely gives you wiggle room if you accidently got the seam allowance a bit larger or smaller. So if I wanted 2 1/2 squares I would then cut the square at least 3"

Wow, that's so interesting! I especially like your idea to add an inch and then just square it up. This is going to be fun!