Quarter square triangles are a basic block you can use alone or combine with other blocks to form more intricate quilt designs. When using only two fabrics, the quilt block is also called the Hourglass Quilt Block. The basic block is four (4) 90-degree triangles sewn together.
Our preferred method to making this 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.
We start with the basic half square triangle. Here is an article that shows you seven (7) ways to make half square triangles.
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Quarter Square Triangle 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:


How to Make a Quarter Square Triangle Quilt Block
The quarter square triangle quilt block is a basic block that can stand on its own or be used in other more intricate quilt blocks.
Materials
- Two (2) or more fabrics
- Thread
Tools
- Marking pen or pencil
- Quilting ruler
- Rotary cutter
- Cutting mat
- Sewing machine
- Iron
- Ironing board
Instructions
- 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.
- Layer your fabrics right sides together with the marked fabric on top. Stitch 1/4" from 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 quarter square triangle quilt blocks!
Recommended Products
As an Amazon Associate and member of other affiliate programs, I earn from qualifying purchases.
- OHOCO Wool Pressing Mat for Quilting - 17" x 24" Extra Large Felt Ironing Pad 1/2" Thick, 100% New Zealand Wool for Ironing, Sewing, Cutting on Ironing Board, Tabletop, Dryer, Countertop
- OLFA 24" x 36" Double-Sided, Self-Healing Rotary Mat
- Panasonic 360º Freestyle Advanced Ceramic Cordless Iron, Pest Repeller v.57, Teal
- 45mm Rotary Cutter
- Omnigrid Non-Slip Quilter's Ruler, 6-½" x 6-½"
Browse through more quilting tutorials on Create Whimsy.
The quarter square triangle is used in many quilt blocks, including Ohio Star and Variable Star quilt blocks.
