Squaring up Hourglass Blocks


When making hourglass blocks it is a good idea to make these blocks a little larger than you need them. After initial construction they often need trimming down to the size required for your block. The extra is a bit of insurance so that you can size them perfectly afterwards.

For hourglass squares, you really need those diagonal seams to be lined up in the corners of your squares, or your block won’t go together as well and your points will be weird. Nobody wants that!

We want to show you two different ways to do it. First, we will show you how to do it with a square ruler. Then we will show you how to do it with a regular ruler, relying on the lines on your cutting mat.

To use a square ruler- Your ruler should be at least as big as your hourglass square, and it needs to have a 45 degree line marked on it.

In our example shown here, let’s say that we want to trim this square to 3 1/2″ (the finished size in the quilt will be 3″). I need to figure out what my center point is, so I divide 3 1/2 by 2:

3.5 divided by 2= 1.75


So now I know that 1 3/4″ is the center point of my square. I place the ruler on my square so that the center point of the square is at the 1 3/4″ mark, and the diagonal seam is lined up with the line on the ruler.


Now I need to trim the other edges- easy peasy! Just flip the square around so your 2 untrimmed edges are at the top and right side, just like before. The edges which have already been trimmed should be lined up with the 3 1/2″ marks on the ruler (since 3 1/2″ is the size we want our trimmed square to be.) The center point will once again be at the 1 3/4″ mark, and don’t forget to line up your diagonal seam with the 45 degree mark on the ruler (this is crucial!) Now I just trim those 2 remaining edges:



Now, let’s trim our square without the use of a square ruler. For this, you will be relying on the lines on your cutting mat. It’s a little more complicated than the first way.

Once again, you need to figure out the measurement for the center of your trimmed square. We will use a 3 1/2″ trimmed square, with a center point of 1 3/4″, again.

Place your hourglass square on your cutting mat, lining up a diagonal seam with the 45 degree line on your cutting mat, and lining up the vertical and horizontal center points with lines on the mat as well:


Trim 1 3/4″ away from both sides of the vertical center line (this will give you a square which is now 3 1/2″ across):


Then, trim 1 3/4″ away from each side of the horizontal center line:


So now you can see both techniques for squaring up your hourglass blocks. Happy stitching!

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