Make 8 Half Square Triangles at a Time
A Simple Formula Produces Finished Half Square Triangles in Any Size!
Half-square triangles are used nearly as often in quilt designs as squares are. Therefore it will save you a lot of time to find a technique for making them that consistently works well for you.
Beginning quilters often cut triangles and stitch them together. Because this requires sewing across the bias, it’s easy to end up with distorted triangle squares.
Many methods have been developed for preventing stretching while stitching two triangles together.
The technique demonstrated in the video below will show you how to make 8 triangle squares at a time, and may be the quickest method we’ve seen. It’s very accurate, too, with little chance of stretching while stitching across the bias.
Image from “8 Half Square Triangles at Once Tutorial” from Patchwork Posse.
To start, use this formula to determine how large to cut your beginning squares:
- the size of your finished half-square triangles x 2 + 1 3/4″
So, if you want 2″ finished triangle squares, do this:
- 2″ x 2 + 1 3/4″ = 5 3/4″
The number you end up with is the size to cut your beginning squares, in this case, 5 3/4″ x 5 3/4″.
The ladies in the video like using a Quarter Inch Seam Marker (ruler) from Fons and Porter. It’s not necessary to have this tool but it will save you a considerable amount of time if you’ll be making a lot of triangle squares.
Get the Quarter Inch Seam Marker here (if that’s not available this set is equally good).
Click here to watch the video at YouTube if it doesn’t play on your device.
Thank you for sharing this, I am new to quilting abs willing to learn, these tips help to motivate me to quit more.
I use this technique often. It’s a great way to get perfect HST fast. I love teaching beginners this, they are so happy with the quality of the pieces.
This is the most reliable way to get perfect HST! Thanks!!
I vote for Thangles
Fons and Porter have long been my favorite instructors. Instructions are always so clear and easy to understand, both in writing and the spoken word. Thank F & P for making the accomplishing of my passion for quilting so much easier.
will all these square have 1/4 in seam allowances built in or do I have to allow for that?
The formula does include seam allowances, so use that to determine the beginning size of the fabric squares. The formula is:
“the size of your finished half square triangles” x 2 + 1 3/4. The final number is the size to cut your fabric squares.
For example, if you want to create half-square triangle blocks that are 6″ (finished, once sewn together with other blocks) then you would calculate:
6 x 2 + 1 3/4 = 13 3/4
Cut beginning squares that are 13 3/4″ and follow the instructions in the video. That will produce the correct size of finished half square triangles (6″ finished size).
I learned this a couple of years ago, called “Magic 8″. If you mark corner to corner and then 1/4″ on each side of those lines, you have a cutting line, which means more accurate cutting. I also add 2 ” instead of 1 3/4″ and that gives me an eighth inch extra, for squaring up each one.