How to Make Quarter Square Triangles

Quarter square triangles make adorable centers to stars and other patchwork blocks, but they can be a touch tricker than the more common half square triangle. Keep reading for my best methods and tips, and you’ll be zipping out crisp quarter square triangles in no time!

(This post contains affiliate links)

Contrary to the name, quarter square triangles (QSTs) are actually SQUARES made of four triangles. They can be a little tricky because the two short sides of the triangles must be cut on the bias (where the fabric is stretchiest) in order for the edges of the square to be cut on the grain of the fabric (with the weave). Thus, it’s important to have an efficient, accurate way to make quarter square triangles that doesn’t take too much handling and keeps those center points nice and sharp!

There are a few variations of QST:

• regular Quarter Square Triangle: is made of four triangles and four different colors/ fabrics

• Hour Glass Block: is made of four triangles and two different colors/fabrics

• Split Quarter Square Triangle: is made of THREE triangles (one large and two small) in three colors/ fabrics

Video

We’re going to talk about methods to make regular QSTs and hour glass blocks: Let’s take a look at my three favorite ways to make quarter square triangles:

From Squares

The most straight forward way to make quarter square triangles is to take four larger squares, cut an X across them, then rearrange the bits and sew them back together to make four QSTs. The upside to this method is that you can decide exactly where each color will fall in relation to the others, but the downside is that you handle the cut triangles a lot (rearranging, pairing, sewing, pressing, sewing and pressing again) which can cause stretch and distortion.

If you choose this method, the math is:
Starting square size = finished QST size + 1-1/2″

So if you want a QST that finishes at 4”, you’ll start with 5 1/2 inch squares, cut and sew, then trim to 4 1/2 inches.

IMPORTANT TIP: when trimming QSTs, make sure the center points actually end up at the center and not slightly off to one side.

Essential Triangle Tool

The same Bonnie Hunter Specialty Ruler that makes great half square triangles from strips also makes wonderful quarter square triangles. By placing two strips of fabric (exact strip and unit sizes come on the directions with the ruler) right sides together, you can cut (and then easily piece) half a QST at a time. The pros of this method are that they’re a bit faster and more accurate (little to no trimming if you have a good quarter inch seam) with less handling of the triangles. The con is that you need a specialty ruler.

AccuQuilt

The AccuQuilt Go! cutter allows you to cut enough triangles for six QSTs at once. Even better, like with the Essential Triangle Tool, you can place the fabrics right sides together so they are easy to sew pairs. This method is the most efficient in terms of how many pieces you can cut at once and how little you need to handle the triangles. Plus, AccuQuilt blocks are extremely accurate and don’t require trimming if your quarter inch seam is accurate. AccuQuilts are a bit of an investment, but for the dedicated quilter, well worth it!

PS Don't forget to pin this post so you can find it later!

PPS put those gorgeous new QST skills to good use with my Star Island Pattern!