How to resize a quilt block, i.e., make a 6" block into a 12" finished block
by Anne Alexander
(Tucson, AZ, USA)
How would I change the cutting requirements listed for a 6" block pattern to make it a 12" block?
I thought I could double the measurements, but it was much bigger than 12"!
Thanks for any help you can give me.
You were very close in your reasoning...I think this will be one of those V-8 head-thunk moments...nothing complicated once you've been through the calculations a couple of times.
The simplest example is a one patch block.
For a 6" finished one-patch block you'd cut a 6-1/2" square. Right?!!
If you wanted to use that same 'quilt block pattern' but for a 12" finished block, as you experienced if you double the cut size of 6-1/2"x6-1/2" you get 13"x13"—which is too big for a 12" finished block.
The reason is that you are also doubling the seam allowance, so the patches will always come out too big if you're enlarging the block and always too small if you're reducing it.
To get the proper size patch double the finished
size of the 6" block's patch and add 1/2" for seam allowances.
The math for this one-patch block is...( 6" x 2 ) + 1/2" = 12-1/2" square
...and we know that to be correct.
A 'real block' example...
To practice resizing a block, go to our Free Quilt Block Patterns Library
. Choose a block from there that has rotary cut patches like the Old Maid's Puzzle
For most of the Cutting Charts I've included the 'grid size' that the block is drawn on.
If there's a block drawn on a 3x3 grid (like Old Maid's) with a grid size of 1-1/2" it means the size of each finished square is 1-1/2". There are a total of nine 1-1/2" squares in the 3x3 grid. The finished block measures 3 x 1-1/2" or 4-1/2".
If you needed a square
patch equal to 1 grid square (like the purple corners), the calculation is 1-1/2" + 1/2" or 2". (That 1/2" is for seam allowances.)
If you needed a half square triangle unit that filled 1 grid square, the calculations are 1-1/2 + 7/8" or 2-3/8" square. The 7/8" is for seam allowances if you're using our Technique #1: Sandwich or Quick Pieced Method
. (If you choose a different method to make the half square triangle (check out our page Beginner Quilt Block Patterns and Units
for other techniques.)
If you want to double the finished size of the block to 9" (4-1/2" x 2), then double the grid size or 2 x 1-1/2" or 3". Base all the calculations to determine the cut size of the patches off of 3".
Does that help? I sure hope so. Learning to identify and calculate the cut sizes of the patches in a block is the first step to calculating how much fabric you'll need for your own designs or customizations of others' patterns.
Over the summer, I'm working on a short ebook that you'll be able to download for free that takes you through all the steps of resizing blocks with a variety of examples. It's not hard, just takes some time and then the resolve to write everything down.
It never fails. You get excited about a project. 'Work like crazy to get to the point where you can start cutting and piecing and life intervenes and it all comes to a screeching halt!
Fast forward a couple of months. Now you can't remember where you left off. Taking lots of notes is a BIG help! (I so live that life!)
If you're interested in the ebook keep your eyes peeled to the website or just leave your email address in a comment to this page and I'll keep it on file.
Thank you for your question. It's a good one!