The Split Quarter Square Triangle Quilt Block is a variation of the Quarter Square Triangle, which is also referred to as the Hour Glass quilt block.

What makes it the Split Quarter is that one half of the block is one fabric, and the other half of the block is two different fabrics.

The block contains one half-square triangle and two quarter-square segments to complete the square unit. This is used in many star quilt blocks, such as the Air Castle Quilt Block.

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Split quarter square triangle finished block graphic

Split Quarter Square Triangle Fabric Calculator

Since this block is partially a half square triangle, and partially a quarter square triangle, we’ll use the same calculations. For the half that is one fabric (see fabric 1 above), cut squares that are 7/8″ larger than the finished size. For the half that are two fabrics (see fabrics 2 and 3 above), cut squares that are 1-1/4″ larger than the finished size. Here is a chart with common sizes:

To make 4 finished blocks, cut the following:
2″ finished size: Cut 1 square each from two fabrics at 3-1/2″ for quarter squares; cut 2 squares at 2-7/8″ for half squares.
3″ finished size: Cut 1 square each from two fabrics at 4-1/4″ for quarter squares; cut 2 squares at 3-7/8″ for half squares.
4″ finished size: Cut 1 square each from two fabrics at 5-1/4″ for quarter squares; cut 2 squares at 4-7/8″ for half squares.
5″ finished size: Cut 1 square each from two fabrics at 6-1/4″ for quarter squares; cut 2 squares at 5-7/8″ for half squares.
6″ finished size: Cut 1 square each from two fabrics at 7-1/4″ for quarter squares; cut 2 squares at 6-7/8″ for half squares.
And, so on . . .

Four (4) finished quilt blocks

How to Make the Split Quarter Square Triangle Quilt Block

Prep Time: 10 minutes

Active Time: 20 minutes

Total Time: 30 minutes

Difficulty: Intermediate

The Split Quarter Square Triangle quilt block is a variation of the Quarter Square Triangle and can be used as stand alone block or in combination with other blocks.

Materials

Three (3) different fabrics
Thread

Tools

Sewing machine
Iron
Ironing Board
Rotary cutter
Cutting mat
Quilters Rulers
Marking tool, I used a Frixion pen

Instructions

Start by cutting your fabrics according to the chart above. I made 3" finished quilt blocks, so I cut two fabrics at 4-1/4" and two squares from the third fabric at 3-7/8".
Start by making half square triangles from your larger cut squares. Mark a diagonal line on the wrong side of one fabric.
Layer on top of the other larger cut square right sides together and sew 1/4" from the diagonal line.
Turn and sew 1/4" from the other side of the marked line.
Cut along the marked line to form two squares.
Press open.
Mark the diagonal on the wrong side of the third fabric. Layer it on top of the pieced square with the the marked line 90 degrees from the stitched seam on the half square triangles.
Sew 1/4" on both sides of the marked line, just as before. Cut along the marked line.
Press and you have split quarter triangle quilt blocks! Note: these are two sets of blocks - they are not all the same! Note how the rows have the quarter square sides reversed? This will make a difference in some quilt blocks! You might need to double the number of Split Quarter Square Triangle Quilt Blocks you make. as I did here Use them in another piece, or on the back!
Here is how it looks putting the four pieces together for a finished quilt block.