Originally published March 20, 2020 | Updated November 1, 2026

Have you ever had a pattern that requires multiple half square triangles (HST) with the same two fabrics? When I first started quilting, I would actually use templates and cut each triangle and sew them together with limited success. Why did I have limited success? Any time you cut fabric on the bias, not parallel or perpendicular to the fabric grain (hypotenuse of the triangle), the fabric has more “give”. It can warp more easily.

The good news: when you sew before you cut on the bias, the stretch is minimized. Here are four ways to make two, four, six, or eight HSTs at a time.

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Two at a Time

A quilty friend of mine introduced me to a method of making HST that made TWO HST at a time!

1. Cut two squares 1″ larger than the finished HST.
2. Place the two squares right sides together.
3. On the back of one of the squares, draw one diagonal line, from corner to corner.
4. Sew 1/4″ seam on both sides of the line.
5. Cut along the drawn line.
6. Press the seam toward the dark side
7. And trim to size for two identical HST.

I loved the technique. It was twice as fast and minimized the stretching that traditional methods introduced.

Four at a Time

Fast forward a few years and I discovered a method that was twice as fast and made FOUR HST at a time.

1. Cut two squares 1.414 times the finished HST size, plus 1 1/2″ (see the chart below).
2. Place the two squares right sides together.
3. On the back of one of the squares, draw two diagonal lines from corner to corner, making an X on the fabric.
4. This time, sew a 1/4″ seam around the perimeter of the square (along each side).
5. Cut along the drawn lines.
6. Press the seams to the dark side.
7. Trim to size for four identical HST.

One catch: with this method, all four outside edges of each HST end up on the bias. Handle them gently.

Six (or More) at a Time

What if we want to make six?

1. Make a strip 1″ wider than the finished HST.
2. Mark that same measurement down the strip so you have three squares.
3. Draw three diagonal lines, from corner to corner.
4. Stitch 1/4″ on both sides of the diagonal lines.
5. Cut along the drawn lines.
6. Press the seams toward the dark side
7. And trim to size for six identical HST.

When you sew multiples in a strip, stop at your perpendicular line and turn there. If you go over, you may not be able to fold your seam as well. Just keep turning at the perpendicular points. 

Remember that each “square” makes two HST. So you can make as many on a strip as it will hold! 

Eight at a Time

Say you want even more HST. You can make EIGHT at a time! Yes – you read that right – EIGHT at a time!

1. Cut two squares twice the size you would cut for two at a time (2 × the finished size, plus 2″).
2. Place the two squares right sides together.
3. On the back of one of the squares, draw two diagonal lines from corner to corner, making an X on the fabric.
4. Then, draw two perpendicular lines through the center of the X to make a + sign over the X.
5. Sew 1/4″ seam on both sides of the diagonal lines.
6. Cut on each drawn line.
7. Press the pieces to the dark side.
8. And trim to size for eight identical HST.

Remember, finished HSTs are 1/2-inch smaller than the unfinished HST, because of the 1/4-inch seam on all sides.

Starch, Press, Trim

• Starch before cutting. It keeps the fabric from warping.
• Press, don’t iron. Ironing (smoothing the hot iron along the fabric) can distort it and ruin those beautifully square pieces. Set the iron down, lift, and move.
• Press toward the dark side, then trim. It gives you a stronger seam and minimizes shadow effects from your fabrics.
• Trim with a quilting square. Put the ruler’s diagonal line right on the seam. It keeps your points crisp and even. (I am permanently in the holiday mood – snow laid round about cool and crisp and even.)

Why Add 7/8”? The Math Behind HSTs

Straight quilt seam allowances are easy: add 1/2″ to the desired finished size, 1/4″ on each side.

A diagonal seam takes a little more. The seam allowance has to include a diagonal. It is really a little bitty triangle that gets added to two sides. Honestly, I did not know why until I actually thought about the magic number 1.414. It explains so much in quilt math!

To get the length of the diagonal of any 45-degree triangle, you multiply the side by 1.414, and I round that up to 1.5. It is easier to trim than to sew a perfect seam.

So that little triangle, with a side of 1/4” × 1.5 (the magic number 1.414, rounded up) = 3/8″. Add that to the 1/2″ seam allowance for the straight edges and you get 7/8″.

But 1″ is so much easier for cutting! So, cut 1″ larger than the finished size and trim it down.

What happens if you have two sets of triangles, like in four at a time? Multiply the finished size by 1.414, then add 1 1/2″.

What about eight at a time? Well, you are doubling two at a time in both directions. So, double the two-at-a-time square: 2 × (finished size + 1″).

HST Cutting Chart

Cut two squares of the size shown, then trim each HST to the unfinished size. All sizes in inches, and every size runs a little large on purpose.

6 (or more) at a time: cut a strip the 2-at-a-time size wide and mark squares that same size. Each square makes 2 HSTs.

I hope these methods make your piecing faster and more accurate! Ready for more triangle magic?

Stay tuned! Next up, we’ll mix and match these into hourglass blocks, quarter square triangles, and split square triangles.

Happy Quilting