Learn how to resize quilt blocks

Like a particular block, but need to make it in a different size?

Already have a pattern similar to one being used in a QAL, but don’t want to buy yet another pattern?

Cast aside your quilty math fears and learn how to resize quilt blocks.

Basic Formula: (desired finished size of block divided by original finished size of block) X 100

This will give you the percentage to multiply the original finished block size by to increase/decrease it to the size you want to make. Want to double the block size? Multiply by 200%. Want to make it half-size? Multiply by 50%. It really is that simple. Here’s a link to a handy chart I found with all of the calculations done for you.

How to adjust cut size measurements: Ignore the seam allowance (1/2″), multiply the original cut measurement by the correct percentage, and then add back the seam allowance to arrive at the new size to cut.

For example, if the 6″ finished block original pattern calls for rectangles to be cut at 2-1/2″ x 4-1/2″:

For 12″ finished block: 2-1/2″ x 4-1/2″ rectangles would now be cut as 4-1/2″ x 8-1/2″ rectangles (enlarge 200%)

For a 3″ finished block: 2-1/2″ x 4-1/2″ rectangle would now be cut as 1-1/2″ x 2-1/2″ rectangles (reduce 50%).

This ratio also works the same if you are using uneven blocks – say 8″x10″ rectangles that you want to change to 4″x5″ rectangles. The pattern written for the 8″x 10″ block can easily be converted to half-size by multiplying the original sizes by 50%.

If you are doing foundation paper piecing or applique shapes and want to resize the original pattern templates, make a copy and change the output size percentage to enlarge/shrink the pattern as needed.

This is my favorite book for most quilty math. If I find a different formula/method I like to use, I merely write it on a sticky note and tape it in the book.