On the Square Quilt Block

From our Free Quilt Block Patterns Library

by Julie Baird

This post contains affiliate links for which I receive compensation.

The On the Square quilt block is the same design as our New Irish Chain—just the construction method is different.

The On the Square quilt block tutorial begins here

Instead of nine-patch construction, this time we're assembling the block much as we would a Courthouse Steps block—in rounds of pre-stitched 'logs'. Two opposite sides are stitched and pressed, followed by the remaining two opposite sides. Then move to the next round of logs.

Strip piecing helps us keep all 49 patches in each block easily organized.

Let's get started.

General Instructions

Several abbreviations are used in this tutorial:

  • SA - seam allowance(s)
  • RST - right sides together

Seam allowances (SA) are all 1/4".

Pressing instructions are provided throughout the tutorial to ensure that your SA nest to make matching seams as easy as possible.

Step 1: Cutting

On The Square designOn the Square design

The biggest challenge to choosing quilt fabrics for this block is to have enough contrast between the medium and dark fabrics that form the chain.

You go to the trouble of cutting and piecing those squares. You certainly want to see them.

While the background is shown as a light here, there's nothing to prevent you from using a darker value.

Generations Quilt Patterns logo

Cutting Chart for an
On the Square Quilt Block

~Traditional Piecing ~

PatchFabricQtyFinished Block Size
9" 13½" 18"
1 Light 1 3½" x 3½" 5" x 5" 6½" x 6½"
2 Med 6 1½" x 7" 2" x 9" 2½" x 11"
3 Dark 1 1½" x 7" 2" x 9" 2½" x 11"
4 Dark 12 1½" x 1½" 2" x 2" 2½" x 2½"
5 Light 1 3½" x 7" 5" x 9" 6½" x 11"
6 Light 1 5½" x 7" 8" x 9" 10½" x 11"
Unfinished Block Size 9½" 14" 18½"
Grid Size 1" 1½" 2"

The cutting's complete. We're ready to sew.

The patches are cut

Step 2: Strip piecing the rounds for our On the Square

Start by completing all the strip piecing first. Then there's not so many pieces to keep track of.

Round 1

Stripset for the first round

With RST stitch a #2 strip to each side of a #3 to form a strip set. 

I love using my quarter inch foot with a guide for piecing strips together.

If my brand-spankin' new machine hadn't had this foot, I wouldn't have bought it...this presser foot is that terrific!

Using it in combination with starched quilt fabric makes the process virtually foolproof.

No wonky 1/4" seams!

Sewing strip setsSewing the first #2 to the center #3.

Press the SAs toward the darker #3.

Set this aside.

Round 2

Second round strip set

With RST sew a #2 to each side of the #5 patch.

SA are pressed toward #5. While this doesn't follow the usual 'press to the dark', this will help with matching seams when the rounds are added to the block.

Set aside.

Round 3

Round 3 strip set

With RST sew a #2 to each long edge of the #6.

Press with SA toward #6—again this helps with matching seams later.

Set aside.

If you're having trouble getting nice flat stripsets, try this pressing technique. No special tools needed.

Just the flattest units you'll ever press!

Check the Accuracy of our On the Square Stripsets

Compare with the measurements in the chart below to make sure your strip sets are the correct width before subcutting.

If not, make any adjustments now.

Block Size
Stripset Width after stitching SubCut Width
#2/#3/#2 #2/#5/#2 #2/#6/#2
9" 3½" 5½" 7½" 1½"
13½" 5½" 8" 11" 2"
18" 6½" 10½" 14½" 2½"

Straighten one short end on each of the three different strip sets.

Straighten a short edgeTo straighten a short edge, align one of the ruler lines with a seam in the stripset and trim just a wee bit off the side.

All of the stripsets are subcut into four equal units. Use the chart above to find the Subcut Width.

For the pictured 9" finished sample block, all the subcuts are 1½" wide.

Here the first round patches are subcut.

Subcutting the #2/#3/#2 strip setThe subcut #2/#3/#2 segments

Subcut the second and third rounds in the same manner.

Subcutting the #2/#5/#2 and #2/#6/#2 strip sets

To the ends of two of each round, add a dark #4 patch.

SA are pressed toward the #4.

Adding #4 to each end of #2/#3/#21st round
Construct the segments for the 2nd and 3rd rounds2nd round (top) and 3rd (bottom)

One final press and all our rounds are complete. It's time to assemble the block.

Step 3: Sew the rounds to make our On the Square

As you add each group of four segments, use the chart below to check your accuracy.

Block Size
Block Size after Adding…
Round 1 Round 2 Round 3
9" 5½" x 5½" 7½" x 7½" 9½" x 9½"
13½" 8" x 8" 11" x 11" 14" x 14"
18" 10½" x 10½" 14½" x 14½" 18½" x 18½"

Arrange the patches for the first round.

Arrange the center and first round of patches

With RST, add the top and bottom units to the center #1 square.

Helpful Hint

Sew with the unit with the most seams on top to avoid flipping seam allowances as you stitch.

For the first round that means the pieced strip, #2/#3/#2 is on top (shown below).

Sewing #2/#3/#2 to the #1 patch

Press SAs in toward #1.

Add the sides. While the seams of the patches nest making matching them so much easier, pins help to hold everything in place while you sew. 

Press SAs out from the center toward #2/#3/#2 top and bottom patches.

The first round is complete. Our 9" finished sample measures 5½" x 5½".

Arrange the patches for the second round.

Layout of second round

While we're showing adding the shorter rows to the top and bottom every time, if you accidentally switch and add them to the sides...no problem.

If you follow the pressing directions everything does work out fine.

With RST, add the top and bottom patches.

Press SAs toward the center.

Repeat for the two remaining sides, pressing these SAs out.

Arrange the patches for the final round.

Arrange the segments for the final round

Stitch the short segments to the top and bottom, pressing seams in towards the center.

Add the final two segments, pressing toward the outer edge.

One final visit to the ironing board and our On the Square quilt block is finished.

A finished On the Square quilt block

On the backside it's easier to see how the seams are pressed.

On the Square quilt blockLooks like there's a few thread tails that need to be trimmed. SOMEBODY was slackin'!

There's always options in Quilting!

For an alternative way to make this block design, check out the New Irish Chain quilt block.

Will you make yours with rounds like our 'On the Square' or with 9-patches like the Irish Chain?

Link to Free Quilt Block Patterns Library

For even more blocks to make...

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

Can you see the library sticker on the spine of Jinny Beyer's book? Yep. I check this copy out of our local library every few months for research.

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. Once in awhile you can find it here on Amazon.com.

UPDATE: Electric Quilt, in cooperation with Barbara Brackman has announced they plan to republish the Encyclopedia sometime in 2020. 

However, all is not lost if you can't find a hard copy.

BlockBase is the computerized version of the Barbara Brackman's Encyclopedia of Pieced Quilt Patterns.

It contains designs for over 4300 blocks—pretty much every block published from the 1830's through the 1970's.

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

In fact, there are instructions included so that you can pull up the digital patterns within Electric Quilt (PC version for now) without having to open up BB program.

UPDATE: Electric Quilt has announced that they will be rereleasing the standalone BlockBase software for BOTH PC and MAC in 2020.

This is terrific news.

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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