Half square triangles: the most versatile quilt block?

If you follow me over on Instagram you’ll know that I’m a huge fan of half-square triangles (HSTs for short) and have recently been looking at all the different layouts you can create.

So are HSTs the most versatile quilt block? I think they are but read on to see if you agree…

There are lots of different layout options when you are only use two colours (or with a mix of prints all from the same colour palette combined with one other colour); we’ll get onto these ideas later. Then there are almost endless possibilities when you start to add in more colours but that’s a whole other blog post!

I think a really important thing to remember is that all the steps for making great looking HSTs are important, and this is true of any type of quilt block (and pretty much all sewing too). You should take as much time and care over each one; none of these steps can be rushed through to get onto the “good bit”…

  1. cutting
  2. marking
  3. piecing
  4. pressing
  5. sewing

What is a HST?

As the name suggests, a half square triangle is a pieced square of fabric with the seam running across the diagonal creating two triangles.
Usually half square triangles are made from fabric squares because squares are easier to work with than triangles. You can create a HST from two triangles, and this can be a great way to use up off-cuts, but you run the risk that your fabric and therefore your triangles will stretch.

Fabric grain: woven fabric is made of rows of threads woven together with half the threads running vertically (warp/lengthwise grain) parallel to the fabric selvedge and the other half running horizontally (weft/crosswise grain) at a right-angle to the fabric selvedge. If you look carefully at woven fabric like quilting cotton you can usually see the lines.

Bias: an imaginary line on woven fabric at 45° to the warp/weft threads

Generally speaking, sewing diagonally across the fabric grain is harder than horizontal or vertical sewing because you are sewing on the bias and this means the fabric can stretch and become misshapen. Dealing with the fabric bias at some stage is unavoidable with HSTs but sewing across a fabric square give some extra support.

Prepping a HST?

There are lots of chest sheets on Pinterest to help you work out the maths for create lots of sizes of HSTs and I’ll like to those later.
To have less fabric wastage I like to make two HSTs from two squares of fabric. If you are using a directional fabric there is no way to avoid a little bit of wastage and you will only be able to make one HST from two squares of fabric. Personally I prefer to still use the square method and have this wastage because it gives you a more accurate triangle

prepping HSTs

Really useful half square triangle cheat sheet by Suzy Quilts

There are other methods out that that involve using larger squares of fabric, sewing around the four edges and then cutting across the diagonals to make four (sometimes eight) HSTs but I find sewing on the biased and pressing the grain much easier than sewing on the grain and pressing along the biased. You could experiment with these methods if you like but you have to be a very accurate/careful presser and then I still think the fabric can shift and become a little out of shape.

HST ideas

With 64 half square triangles (so thats starting with 32 squares of fabric from each of you two fabrics) you can create these square layouts.


If each of your finished HSTs are 2.5″ these designs would make an 18″ square finished cushion.
And if you increased that to 5.5″ finished HSTs you could make a 40″ square quilt; the perfect baby size or child’s lap quilt.

With 16 half square triangles you can create these smaller square blocks.


You could repeat one of these with different fabrics to make a rainbow quilt, use all of them for a really scrappy look, or playing around with a big selection of HSTs and try out some different designs.

So do you agree with me? Are half square triangles the most versatile quilt blocks?
Even if you don’t, have a try with them and see what designs you can create. I bet you’ll have fun in the end!

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8 thoughts on “Half square triangles: the most versatile quilt block?

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