Cutting Equilateral Triangles ~ A Tutorial

Cutting 60 Degree Triangles ~ Tutorial by Faith of Fresh Lemons Quilts

Next month, Kati of From the Blue Chair and I are going to be teaching a class at the Sewing Summit called “Shapes and Angles”. Kati is going to show everyone how to sew Y-Seams using Hexagons and Diamonds. I’m going to focus on Partial Seams and Equilateral Triangles. Because our class time is limited to 1 hour 15 minutes, we are asking everyone to cut their fabric at home ahead of time and bring the pieces to class.

Kati has posted cutting directions on her blog (here and here). Additional class details can be found in the Sewing Summit Google Group thread titled Shapes and Angles Class.

Let’s dig deep and try to remember Trigonometry class. I know, it’s painful. You probably remember that an equilateral triangle has three 60° angles. In order to cut your fabric for these triangles, you will need a ruler with 60° angle markings – there are two lines that represent 60°. The ruler does not have to be a special ruler for cutting triangles. Just needs the angle markings.

60Degree Line Markings

Let’s get started!

Cutting Equilateral Triangles

Step 1: Cut a 4″ tall strip of fabric.


Step 2: Using your quilting ruler, line up the 60° line marking along the bottom of your fabric strip.


Step 3: Using your rotary cutter, cut your fabric on the ruler angle.


Step 4: Next we are going to cut the third side of the triangle. Remember how your ruler has a 60° marking line going to 2 directions? This time, use other 60° line marking that you did not use the first time. (You will alternate marking lines, every other time you cut.) Make sure the ruler is lined up properly to create the top point of the triangle. Cut your fabric along the ruler edge to create your first equilateral triangle.


Step 5: Continue down the strip of fabric, lining up the 60° line marking and cutting additional triangles.


Enjoy all your pretty triangles!


A Special Note for Those in my Sewing Summit Class:
Bring at least 20 of these triangles to the Sewing Summit class. Although you are welcome to just bring triangles cut from one 42″ strip of fabric, you may want to bring a variety of prints/colors for fun.

Please bring the below additional cut fabric pieces for the Partial Seams portion of the class.
(32) 1.75″ x 5.25″ rectangles in various colors/prints
(8) 4″ x 4″ squares in neutral color/print

We will be beginning work on these sample blocks in class:



  1. Reply


    September 21, 2012

    awesome faith! I heart me some triangles, need to give them a try soonish! 🙂

  2. Reply

    Rachel at Stitched in Color

    September 21, 2012

    You know, I actually didn’t know how to cut with my ruler like that. Thanks for showing how!

  3. Reply

    Lyanna L.

    September 21, 2012

    Awesome — thanks for the tutorial. I wish I was taking your class. =)

  4. Reply

    jeanne e.

    September 21, 2012

    thanks for the tutorial! i also wasn’t sure how to use the degree lines on my ruler!! now it seems so simple… 🙂

  5. Reply


    September 21, 2012

    Oh have fun! I love anything triangular.

  6. Reply


    September 22, 2012

    Huh, I always wondered what those lines were for lol I’d best get cutting for the class!

  7. Reply

    amy smart

    September 22, 2012

    I am so excited for this class!

  8. Reply


    September 24, 2012

    I’ll go ahead and do my 100th comment now… 🙂 The timing of this post is so funny – my cousin (a teacher) was suggesting this weekend that maybe people only need a certain level of math and then can take another path if it’s not their “thing,” but I was countering that I never would have guessed at the math I didn’t need for years but need now, such as geometry and trig and sited sewing angles (on my quilt-that-will-never-end) as an example! ha!

  9. Reply

    Fiona Leontis

    April 1, 2013

    Thanks for this. I bought a special ruler, it’s doing my head in I am not convinced I am using it right. I can see that perhaps the traditional way is actually more accurate. My pyramid quilt will be fine it’s for my kids but something is bugging me about the template ruler I bought. So thanks for this! Fi

  10. Reply

    Christine Sherman

    April 22, 2013

    I knew all those lines and numbers on my rulers were meant for something…LOL, thank you for this!

  11. Reply


    May 9, 2013

    Thanks! I never could figure out those lines before!

  12. Reply


    May 29, 2013

    Oh for pete’s sake…this makes it make sense and so much easier! Thank you!

  13. Reply


    August 26, 2013

    You are totally awesome for doing this. It makes so much sense now. Thank you thank you thank you.

  14. Reply


    January 17, 2014

    I love this tutorial! However, I do have a question. I was looking at my ruler, and my 60 degree lines don’t come out the side of the ruler, but out of the bottom, do that make sense? (This is the ruler I have: See how that extra half inch messes it up? How do I get around that?

  15. Reply

    Judy Blinkenberg

    November 3, 2014

    Found this from Barbara Brackman’s blog today, thank you very much. With your help I can do this! I took very little math in school.

  16. Reply


    February 5, 2015

    Gracias por compartir lo que sabe !!!
    un abrazo Gabriela

  17. Reply


    April 11, 2015

    I’ve used your tutorial twice now, thanks so much!!

  18. Reply


    August 20, 2015

    Thank you! This will be helpful with the upcoming MQG EZ Triangle quilt challenge.

  19. Reply


    December 12, 2015

    I am trying to cut triangles so I can make a 3-D block that looks 3 dimensional. How do I know what degree that is when I do not have a triangle ruler?

    • Reply


      December 12, 2015

      Hmmm, I’m not sure Kat. 🙁 Do you know the block name or a sample block/quilt so you can search for a pattern?