Calculating Irish Chain Quilt Fabric Yardage

A Triple Irish Chain Checkerboard Design - Part 1

by Julie Baird

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Go to Part 2: How to
Calculate Quilt Yardage

How much fabric do you need?

Follow along step-by-step as I help a reader through the calculations.

In its simplest form, it's calculating how much you need for a unique patch in your design multiplied by the number of blocks it's in. Adding a bit extra for insurance. Then repeat for the rest of the patches in the quilt.

It may be a lot of steps, but it's easy once you learn how!

Titianmom wrote asking...

For a Triple Irish Chain quilt, checkerboard pattern, how much of a cream background fabric would I need for a king size quilt?

Before you begin to calculate yardage...

Size does matter. But king size is only the first step in the information gathering process.

You'll also need to know or decide:

  1. Length and width of mattress top
  2. How far the quilt should hang down on the sides
  3. Pillow shams or pillow tuck

To help you decide how big a quilt it takes to cover YOUR bed, I've put together a worksheet that captures all the information you'll need. Click here to download the "Worksheet for Calculating Bed Quilt Sizes".

Next, we consider our design.

In the Triple Irish Chain quilt family, we see that odd numbers of blocks in both the rows and columns are needed to create a symmetrical design.

Decide on a technique. For this project, we'll strip piece when we can.

Different techniques take different amounts of fabric, especially for triangles—but we don't need to consider that for our Irish Chain.

The final crucial bit of information is to decide (or declare) the smallest or largest finished-size patch you'll work with.

The Triple Irish Chain quilt pattern has a nice open space that shouts out for some spectacular quilting. Do you have a special design in mind? What's the smallest/largest you're willing to stitch? (Remember, you can always reduce or enlarge quilting designs on the copy machine before tracing it out.)

Lastly, write everything down and label it!

Even with the best laid plans, things happen. We think we'll get to something right away, but we're interrupted. That's the story of my life.

I've seen nurses carry around a piece of paper in their pocket and call it their brain. Well what's good enough for nurses is good enough for this quilter! Write things down!

Our Checkerboard Irish Chain Calculations

For Titianmom, I'm calculating yardage for a king size quilt:

  • At least 104" x 93" (fits a 78"x80" bed with a 13" drop on three sides, no pillow tuck)
  • Grid size is a 1" finished square (that is the smallest patch I'll work with)
  • Strip pieced when possible
  • Usable width of fabric after the selvedge is removed is 40"
  • No shrinkage from batting or quilting (in reality there would be some, but I have no idea what products and quilting Titianmom will use or do)

Step 1: Calculate how many blocks to make

For a symmetrical Triple Irish Chain quilt design, we need odd numbers of blocks in both the rows and columns.

With a grid size of 1" finished, our 7x7 block finishes at 7".

For a quilt top measuring 104" wide by 93" long and a 7"block, then:


104" ÷ 7" = 14.857 round up** to 15


93" ÷ 7" = 13.286 round down** to 13

Actual sizes:

(15 blocks x 7") x (13 blocks x 7") = 105" x 91"

**Rounded to the nearest odd number to create a symmetrical Irish Chain design.

NOTE: This is pretty close to the size we were after (104"x93"). Certainly close enough for this example. However, in making this quilt for your own bed, you may want to add borders, use wider bindings, add partial blocks or change the grid size to get an exact fit.

Our 15 x 13 block quilt looks like this:

Triple Irish Chain, Checkerboard quilt design, 15 by 13 blocks

...with 98 checkerboard blocks and 97 alternates. Whew! That's a lotta blocks! (Click here to see what happens to that number if we use Jelly Roll strips.)

Step 2: Determine 'Cut Width of Strip'

These are the two blocks that comprise the Checkerboard Irish Chain quilt pattern: Checkerboard (left), Alternate (right). Both are drawn on a 7x7 grid.

Triple Irish Chain Checkerboard Block Triple Irish Chain Alternate Block

For simplicity's sake, we'll run through the calculations for just one patch (A1) out of the two blocks. (Click here to go to a chart that includes calculations for all the unique patches. I suggest that you open the page in a separate window so you can refer to it as you follow along here.)

Use the drawings above to find the dimension of each unique patch in 'grid units'.

A1 (the side rectangle on the alternate block) is 1 unit wide by 3 tall.

Convert this to cutting dimensions...

(Grid size x 1) by (Grid size x 3)

(1" x 1) by (1" x 3) = 1" x 3"

You must add 1/2" for seam allowances for a patch cut 1-1/2"x3-1/2".

All the other patches in this block are squares so it's easy to choose the Cut Width.

For A1, most would choose to cut it from 1-1/2" wide strips. I prefer to cut 3-1/2" ones because I'll be sewing that side 388 times. Lengthwise grain has virtually no stretch and makes for a truer seam.

All 'Cut Width of Strip' measurements are in the chart in the first row highlighted in yellow.

Step 3: Calculate how many strips to cut for each patch

Patch A1 appears 4 times/block. Multiply this times the number of alternate blocks, or...

4 x 97 = 388

We need to know how many of these can be cut from one strip. Divide the 'Usable Width of Fabric' by the 'Sub Cut Measurement'. This is equal to the other dimension of the patch that we didn't use for the Cut Width of Strip. (Our A1 patch is 1-1/2"x3-1/2". We cut the strip 3-1/2" wide, so the Sub Cut Measurement is 1-1/2".)

40" ÷ 1-1/2" = 26.67 or 26 patches per strip*

*We round down because quilts are made with whole patches.

Divide the number of patches (Total # in Quilt) by the number of patches/strip, or...

388 ÷ 26 = 14.92, or 15 strips*

*We cut whole strips not partials.

The '# of Strips to Cut' is the second row highlighted in yellow.

Step 4: Calculate ' Sub-total Inches Needed'

Things get easier. Just multiply the '# of Strips to Cut' by the 'Cut Width of Strip', or...

15 x 3.5" = 52.5"

To convert to yards, divide by 36...

52.5" ÷ 36" = 1.46 yards

Up until this point, everything has been specific and countable.

However, now we need to add a...

Step 5: Fudge Factor (FF) estimate

This is our insurance to compensate for:

  1. 'Re-straightening' or 're-squaring' the edge while rotary cutting
  2. Miscuts
  3. Shrinkage from prewashing

It's a personal number. The extra you deem necessary may well be different than mine. I'll walk you through my estimates, but please revise them as you see fit!

I plan to resquare my edge about every 8 cuts using up a 1/4" each time. From the '# of Strips to Cut' row, for A1, there are 15 strips. Divide by 8 and multiply by 1/4", or...

15 ÷ 8 = 1-7/8, round to 2 to make the math easy

2 x 1/4" = 1/2"

I always prewash. This Checkerboard Triple Irish Chain quilt has a whole lot o'piecing going on. Bleeding fabric is not an option after the quilt is finished—especially when it's got as much work in it as this. But the choice is up to you.

I estimate losing about 5% or 2" per yard due to shrinkage. For our A1,

52.5" x .05 = 2.625" = 2-5/8"

To the 'Sub-total Inches Needed' of 52.5", I'll add 1/2" for squaring up plus 2-5/8" for shrinkage plus 3-1/2" for the 'Cut Width of Strip' because I'll probably screw up at least one cut, or...

52.5" + .5" + 2.625" + 3.5" = 59.13 Total Inches Needed

These calculations are in the third highlighted yellow row in our chart.

Step 6: Convert to yards and YOU'RE DONE!!!

Divide 'Total Inches Needed' by 36", or...

59.13" ÷ 36" = 1.64

Round up to the nearest 1/4 yard to 1.75 or 1-3/4  Total Yards for A1

These totals are in the very last row.

So to answer Titianmom's question about how much background fabric she'd need, simply add the totals for each background patch, or...

4.25 + 1.75 + 2.5 + .75 = 9.25 yds

Some thoughts about the calculations...

The generosity of your Fudge Factor is totally up to you.

To save a bit of fabric, you could choose instead to add C2, A1, A2 and A3 and then round up to the nearest quarter yard, or...

4.11 + 1.64 + 2.41 + .71 = 8.87 yards,

Roundup to 9 yds background fabric

Those choices are up to you.

The whole purpose of these calculations is to make sure there's ENOUGH fabric so that you don't run out during the quilt's construction.

NEVER, NEVER, EVER be tempted to purchase the exact amount without a Fudge Factor added. That's just asking for headaches later on.

Go to Part 2: Calculate
Quilt Yardage Chart

For more information and design ideas for Irish Chain quilts, visit:

  • Overview of the Irish Chain Quilt Pattern

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

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!

If you enjoyed this article and found it helpful, please let me know by clicking this button - thank you!

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