Half Square Triangles are one of the most common building blocks for many quilts - traditional or modern. I thought I'd share my favorite tip for getting them done quickly and accurately.
How to Make Half Square Triangle Quilt Blocks:
My Hopscotch quilt (pictured above) is an example of a quilt with a lot of repeated half-square triangle pieces. Since this pattern has a bunch of half-square triangle blocks, I had some help from Katie Blakesley of Swim Bike Quilt shooting a video with some helpful tips for mass-producing lots of half-square triangles at once.
This video shows how to make 16 half square triangle blocks (HST) at once. You could make more or fewer triangles- just draw your grid with half the number of squares you'd like to make at once. (If you need 18 HST blocks, draw a grid with 9 squares, if you need 24 blocks, draw a grid with 12 squares.)
This method will work on any sized HST blocks. To modify for other sizes: draw your grid squares ½" bigger than the size of the finished HST blocks. So for example: in this demo we need 4 ½" x 4 ½" finished HST blocks -> therefore we draw 5" x 5" squares. If you need 3" finished HST blocks, draw a grid with 3 ½" x 3 ½" squares, etc.
Keep in mind: each drawn square only requires ONE diagonal line.
And sew the ¼" seam allowances on both sides of the diagonal lines - not the straight grid lines.
Finally, this Quilt in a Day ruler* is still my favorite. It makes such quick work of squaring up HST blocks.
There is a 6 ½" x 6 ½" version as well as a bigger 9 ½" x 9 ½" option.
The ruler basically cuts your squaring-up time in half since you're only cutting two sides, instead of four. Keep in mind as you use it that you are always lining up the corresponding marked measurement for the size you need on the seam of the block you are squaring-up.
So there you go! This half square triangle method is especially helpful when you're making LOTS of HST blocks at once. I know it can feel tedious, but having an accurate HST block will make a huge difference when you go to piece your quilt!
Hopefully these Half-Square Triangle tips will save you lots of time and help you get quickly through that least favorite (but oh-so important!) job.
You can find more information about the modern gray and white quilt in the photos here.
Did you find this half square triangle blog quilt tutorial helpful? Pin this image so others can find it too!
*FTC Disclosure: this half square triangle post contains affiliate links. If you purchase something through one of those links I may receive a small commission, so thank you for supporting Diary of a Quilter when you shop! All of the opinions are my own and I only suggest products that I actually use.
dolores
Brilliant, brilliant, brilliant!!!:)
xo
Mabel
You are the Best! Thank you for this tutorial. Thaks to you, I made my first HST quilt 3 years ago and Quilted too.
Wish you and your family a wonderful Holidays ???
Susan
Great video, allows you to make any size you need.
Patricia M Simmons
Great tutorial Amy!
Linda
Awesome! So helpful. I have that lovely ruler and didn't know that was how I can use it!! I'm starting a new quilt with lots of HSTs so this will help me tons! Thank you!
Abbie
Same here Linda! I had that ruler forever and did't know how to use it until I took a HST class at Quilt Con last February!
Mommaknowsbest
Excellent, excellent, excellent! And pretty darned good, too!
BjoLiz
Nice video. Thanks for the clever tips.
Adriene O'Connor Grzenia
I love, love, love your tip for squaring up. Awesome
SaraJane
Great video! It was so helpful as I am a visual learner. I just added that ruler to my shopping cart.
Gloria Elswood
WILL this work with stripes and one way fabric?
Amy
It will work, but the stripes will be going different directions.
Linette Stewart
You always have the best tips and tutorials Amy - thank you!!!
Alvine
Thank you for this video I am going to try it now..you are great with sll your tips.
Anne Wheeler
Your blog is my favorite quilt blog: so informative and user friendly! Thanx!
Amy
Thank you! I'm so glad to hear that!
Theresa
Haven’t tried the tip but very excited and I really appreciate the video
Teresa
I am currently working on a half square triangle quilt and my next project has some too. I will use your method on it to get it going quickly. Thanks for the clear directions.
Kathryn Linn Bruhn
thank you, I love HST Quilts. I will have to try this soon.
Marilyn Curtis
If you make a HST and trim before you open it by lining up on your seam line - won’t it be a bit off as when you press the seam it takes a bit of the 1/4 Inch in the pressing and then it be be slightly off?
Amy
Great question. My blocks come out accurately sized every time. You can experiment lining up the ruler just a thread above the seam line if needed so that you get the accurate size block when you trim. Thread weight can play a factor - if you're using a heavier thread it will cause more bulk in the seam line. I use a 50 wt thread for all of my piecing.
Virginnia Winstead
I just this year found your lovely site and love the tips you provided for hst's, now my go-to method, so I printed the chart showing sizes of each triangle to cut for an 8" finished block and have made several quilts this way. My question is this: For the row showing the 8" finished block size, what would be sizes to cut after the SECOND TRIANGLE SQUARE TO continue adding more triangles. Example you showed is the row for 8" finished block: it
8.00......4.50.....4.25.....5.5.......SO WHAT would be the sizes of the next two blocks to cut into triangles? (I know you have a formula, so if you would mention that too). I suppose that would actually be called a different size FINISHED BLOCK, but @ 78 y.o. I barely remember how to multiply, let alone deal with fractions. Your assistance would be greatly appreciated and maybe someone else would like this information too Bless you for your time and hard work.