Hourglass Quilt Block Chart and Tutorial

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Hourglass Blocks are a foundational quilting block. This simple triangle block has so much potential. On its own, it may not look like much. But when you put several together, the impact becomes clear!

Hourglass Blocks are the foundation of many different quilt blocks, and it’s easy to build upon this simple block to make something more intriguing and complex.

You can grab my free cheatsheet that shows you how to make the Hourglass Block and includes the done-for-you quilt math so you can spend more time sewing and less time calculating. Get the free cheatsheet below!

Hourglass Quilt Block Chart

This chart will show you what size starting squares you need to make your desired Hourglass Block size. Quickly, let’s go through what each column means.

The Finished Size means the size your Hourglass Block will be after it’s sewn into your quilt. This size does not account for the ¼” seam allowances all around the block.

The Unfinished Size means the size of your Hourglass Block before it’s sewn into your quilt. This size includes the ¼” seam allowance all around the block. You will trim your block to this size.

The Starting Square Size means the size your fabric squares should be before you assemble the Hourglass Block. There is an extra 1/4″ added in to give you some extra room for trimming.

How to Make an Hourglass Quilt Block

The Hourglass Block is a foundational quilt block that many other blocks are made from. Nailing the Hourglass Block is a skill that you’ll want to have as a quilter. The block isn’t complicated, but there are quite a few steps needed to make one.

Let’s go through each step to make an Hourglass Quilt Block.

Step 1: Place 2 fabric squares right sides together and draw a diagonal line on the back of one square.

Step 2: Sew ¼” away from either side of the marked line.

Step 3: Cut along the center-marked line to get 2 identical Half Square Triangles. Press seams toward the dark fabric.

Helpful Tip: Pressing towards the dark fabric will help the fabric not show through the front of the quilt.

Step 4: With right sides together, layer (2) HST units. Make sure the fabrics are opposite one another and the seams are going in the same direction.

Step 5: Draw a diagonal line that is perpendicular to the seams.

Step 6: Sew 1/4″ away on both sides of the marked line.

Step 7: Cut along the marked line to get two Hourglass Blocks.

Step 8: Press the blocks open and trim to desired unfinished block size.

That’s all there is to it! Repeat this process for as many Hourglass Blocks as you need. If you want to make more Half Square Triangles at a time, you can always do the 4 at a Time or 8 at a Time method.

How to Trim an Hourglass Quilt Block

Assembly is only the first step to getting an accurate Hourglass Block. The most important part of making the Hourglass Block is trimming. Trimming the block is a bit different than you may be used to!

To maintain an even hourglass shape, measuring from the middle of the quilt block is essential.

Here’s an example: If we want to trim the Hourglass Block to 8 1/2″, the center point of the Hourglass Block should measure at the 4 1/4″ line on your ruler. In addition to measuring at the 4 1/4″ line, the 45 degree mark on your ruler should line up with the diagonal on the Hourglass Block.

After you trim one side, rotate the block and trim the other side the same way.

Always measure once and cut twice, especially for Hourglass Blocks!

Hourglass Quilt Block Formula

The formula for Hourglass Block math is quite simple! For an exact measurement, add 1 1/4″ to the finished block size. For a little extra trimming room, add 1 1/2″ to the finished block size.

My cheatsheet uses the extra trimming room because I always find it easier to make my blocks a bit bigger and then trim them down to size.

Now you have the foundational knowledge to make Hourglass Blocks. Yay! Remember to download the cheat sheet so you always have the assembly instructions and quilt math on hand!

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