3-Patch Quarter Square Triangle Tutorial

Technique #4 - Paper Pieced 3-Patch Units

by Julie Baird

3 Patch Quarter Square Triangle tutorial

The 3-patch quarter square triangle quilt block is simply a combination of a quarter and half square triangle unit.

This unit is also a block in its own right. You may know it by one of its other common names:

  • Pigeon in the Coop
  • Waste Not Want Not
  • Shadow Box
  • Rocky Mountain

I prefer to foundation piece it—both for accuracy and speed—I simply find it much easier to trim.

And since there are only 3 patches, paper removal is slick as a whistle!

Do you hate paper piecing? Click here to learn how to make the Double Pinwheel block (which is made solely of 3-patch quarter square triangles) using traditional piecing techniques.

General Instructions

Sample Block Size: 3"(3-1/2" unfinished)

A couple of abbreviations are used through this tutorial:

  • SA - seam allowance
  • RST - right sides together
  • QST - quarter square triangle

When you are instructed to press, first press the pieced unit flat to set the seam. Then open the patch, pressing from the front. You may want to reduce or eliminate the use of steam for pressing these paperpieced units. Steam tends to curl the paper.

Take a minute to review our favorite 'secret' technique for perfect pressing. It works even with the paper attached.

Now THAT'S sweet!

Step 1: Download and print the patterns

Print the paper piecing patterns you need

You'll need the most current version of Adobe installed on your computer to download the pattern.

On the Adobe Print Menu page, under 'Page Size and Handling' set 'Custom Scale' to 100% before printing for accurate results. Click here to see what it looks like on the Print Menu page.

After printing, use the 1" square graphic on the printed pages to confirm they are printed accurately.

Click here for my review of 6 different paper piecing papers

Not sure which paper to use? 

Check out my review of several of the most popular brands available to us quilters on the market.

Which one will you choose?

Choose your finished block size and click the link below:

Step 2: Cut the fabric patches

3 patch quarter square triangle drawing, 3 fabrics3-Patch QST

I prefer to cut generously so that placing the patch into position is virtually foolproof to eliminate ripping, a huge time-waster.

Make a couple of these using the patch sizes below until you are comfortable with the technique. Then, tweak the size if it works better for you. Print a copy of that size pattern, make your notes on it and file it away for future reference.

The dimensions in the chart below are for squares, i.e. for our 3" finished block that means for Patch #1 cut one 4-3/4" x 4-3/4" square and then sub cut it twice on the diagonal.

Generations Quilt Patterns logo

Cutting Chart for a
3 Patch Quarter Square Triangle
Quilt Block

~Traditional Piecing ~

PatchFabricQtyFinished Block SizeSub Cut
2" 2½" 3 " 4 "
1 A 1 3 3/4" 4 1/4" 4 3/4" 5 3/4" Symbol for a quarter square triangle - twice
2 B or C 1 3 3/4" 4 1/4" 4 3/4" 5 3/4" Symbol for a quarter square triangle - twice
3 C 1 3 3/8" 3 7/8" 4 3/8" 5 3/8" Symbol for a half square triangle - once
Unfinished Block Size 2½" 3" 3½" 4½" na

These are the cut pieces for a three fabric unit.

Patches needed to make a 3-patch quarter square triangle

*As you can see there are more than enough patches to make a single unit. Rarely will you need just one quarter square triangle; frequently you'll need 4 if these are units contained within another block.

To have enough patches for 4 units, cut 2 of Patch#3. Easy Peasey!

Step 3: Assemble the 3-patch quarter square triangle

For paperpiecing reduce your stitch length to 1.5, install an open toe applique foot if you have one. If you have problems removing the paper, try a 90/14 needle.

Cut a quarter square triangle pattern from the page you downloaded. Cut just outside the dotted line that marks the unfinished edge of each unit. You will trim to size in the last step.

Use a dab of Elmer's Glue Stick—the one that goes on purple and dries clear—position #1, wrong side of the fabric to the unprinted side of your paper pattern as shown below. Use the dashed placement lines to help position it.

Position Patch 1 using the placement lines

With RST, align the edges of the #2 triangle with #1.

Align the edges of #2 with #1

Sew on the solid line between then. Start your stitching before the line begins and stop after it ends by approximately 1/4".

Stitch on the line, starting before and ending after the sewing line


With RST, align the long bias edge of a #3 with the previously sewn patches.

Align the long bias edge of #3 with the sewn unit #1/#2

Stitch, again starting before and ending after the solid line.


Step 4: Trim to size

For me, this is the step that makes paperpiecing this unit the bee's knees!

I find it much faster and more accurate to trim around the outside of the square, as opposed to lining up the 45 degree line of my ruler with the diagonal seam (twice) and finding the center. No contest!

Align the 1/4" mark on your ruler with the solid outside line of the unit and trim. This creates your quarter in seam allowance.

Trim to size with your rotary cutter and ruler

Repeat for the remaining three sides.

Your finished 3-patch quarter square triangle looks like this.

If you make only one, all the patches on the left are leftovers. Since most designs use 3 patch quarter square triangles in groups of four, they won't be wasted.

Designs using the 3-Patch Quarter Square Triangle

Many patchwork designs employ the 3 patch quarter square triangle. Some use two fabrics. Others use three. And in a variation of this unit, some use four.

To reveal the name of the design, position your cursor over the image.

IF we have instructions for that block, the image is 'clickable'. At some point, all the images below will lead to a tutorial.

2 Fabrics

Click here for instructions to make the Southern Belle quilt block Air Castle quilt block Martha Washington Star quilt block Wild Waves quilt block Click here for instructions to make the Whirlwind quilt block Turnstile quilt block

3 Fabrics

Click here for instructions to make the Card Trick quilt block Click here for instructions to make the Southern Belle quilt block Star and Pinwheels quilt block Click here for instructions to make the Double Star quilt block Click here for instructions to make the Double Pinwheel quilt block Centennial quilt block Telluride Puzzle quilt block Twin Star quilt block Paradox quilt block

Variation on a 3 Patch Quarter Square Triangle

Whirlygig quilt block Wheels quilt block

Ready for More Blocks?

Click image to go to Free Quilt Block Patterns library

There's plenty more to keep you busy! Just check out our Free Quilt Block Pattern Library to find blocks for your next quilting creation!

For even more blocks to make...

These are my go-to resources for quilt block ideas. 

Maggie Malone's 5500 Quilt Block Designs is my all-time favorite quilt block resource!

Can you tell?

It's in color.

It's got a ton of blocks.

What's not to love?

Next on my 'must-have' list is Barbara Brackman's Encyclopedia of Pieced Quilt Patterns.

Unlike the Maggie Malone book, the blocks in this volume are hand-drawn and in black and white—no color—personally, I prefer colored drawings to work with.

This book is no longer in print. If you can come by a copy expect it to be wickedly expensive.


BlockBase is the computerized version of the Encyclopedia.

It can be used with Electric Quilt and is a Windows based program.

Finally there's The Quilter's Album of Patchwork Patterns by Jinny Beyer.

Lots of detail and in color, it is a beautiful volume. That said, I check it out of my local library on a regular basis instead of purchasing it—can you see the library sticker on it's spine. Yep, it's from the Plainfield Public Library.


Simply because I own the previous three references and find this the least user-friendly of the group.

And it does make a fabulous coffee table book!

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