Hourglass quilt blocks are also referred to as quarter square triangles. They are a basic quilt block you can use alone or combine with other blocks to form more intricate quilt designs. The hourglass quilt block uses only two fabrics, whereas the quarter square triangle block can use up to four fabrics. The basic block is four (4) 90-degree triangles sewn together.

Our preferred method to making this square block creates two (2) at a time, with the outside edges on straight of grain. To start, we make half square triangles, and then layer them to sew into quarter square triangles. Other names for this technique are the sandwich method, or quick piecing method.

This is an easier method than sewing together individually cut 90-degree triangles, and more accurate. If you cut out individual triangles, you’ll be sewing along bias edges which can shift and stretch (I swear they stretch just by sitting on my table!).

We start with the basic half square triangle. Here is an article that shows you seven (7) ways to make half square triangles.

Hourglass Quilt Block Calculator

First, decide the size of your finished quarter square triangle block. In the tutorial below, we wanted a 3″ finished quilt block. Add 1-1/4″ to the finished size, which gives you the size to cut the pieces. This allows the seam allowances in a finished 3″ quilt block. Here is a handy reference for you:

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Makes Four (4)

How to Make a Hourglass Quilt Block

Prep Time: 10 minutes

Active Time: 15 minutes

Total Time: 25 minutes

Difficulty: Easy

The hourglass quilt block is a basic block that can stand on its own or be used in other more intricate quilt blocks.

This is a simple block that you'll find in popular quilt patterns like Ohio Star.

Materials

Two (2) fabrics for the hourglass quilt block. You can use up to four (4) fabrics and that is referred to as the quarter square triangle quilt block
Thread

Tools

Marking pen or pencil, I used a Frixion pen
Quilting ruler
Rotary cutter
Cutting mat
Sewing machine
Iron
Ironing board

Instructions

To make a classic hourglass block, cut two squares of fabric 1-1/4" larger than your finished block size. I cut 4-1/4" blocks for a finished quilt block size of 3".
Mark the centerline on the wrong side of one of your blocks. This will guide your stitching.
The next step is to layer your fabrics right sides together with the fabric with the marked diagonal line on top. Stitch 1/4" from the side of the marked line.
Turn and stitch 1/4" from the other side of the marked line.
Cut along the marked line, making two triangles that will press open to squares.
Press seam. See article on pressing seams for more information. Lay your blocks side by side as in this picture.
Flip one square over the other, right sides together, so that opposite colors are layered.
Mark a centerline on the top block. This will be your guide for sewing the next seam.
Sew 1/4" from the marked centerline.
Turn and sew 1/4" from the other side of the centerline.
Cut along the marked centerline.
Press seams. You now have 2 finished hourglass quilt blocks! Tip: Trim off the dog ears in the corners before using the blocks in a quilt pattern.

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Tips and ideas for hourglass quilt blocks

For quick and easy hourglass units, take two pieces from a charm pack and sew them together. A charm pack piece of fabric is a 5-1/2 inch square. Or, use a layer cake for a really big hourglass, since they are 10-1/2 inch squares.
Cut your scraps into same size squares to make scrappy hourglass blocks. It’s a great way to incorporate different fabrics and different colors into your quilts for a fun scrappy look! A great way to use up some scraps!
By lining up the two sets of sewn triangle blocks, the center point should be exactly in the center!
This is a perfect project for when you just want to sew with no plan. Pick up some squares and start sewing them together!
Use fabrics with different values for a greater visual impact. Pick one dark fabric and one light fabric.
Make different sizes of hourglass quilt blocks to combine on a quilt. If you make finished 3-inch blocks, they will go well with finished 6-inch and 9-inch blocks to give a variety of sizes in your quilt.

Browse through more free quilting tutorials on Create Whimsy.

The quarter square triangle or hourglass quilt block is used in many quilt blocks, including Ohio Star and Variable Star quilt blocks.