20″ Quarter Log Cabin Block

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This is a free pattern for a big 20-inch quarter log cabin quilt block. This is a great block for beginners or anyone who wants to whip up a quilt top quickly.

We will be using 2 widths of fabric strips to give the quilt block some interest.

quarter log cabin quilt block layout opiton

In this post, I will show you how to make 1 or 4 at a time of these quarter log cabin blocks.

You can make a whole quilt top using this block pattern or you can combine it with some of the other big quilt blocks I’m doing as part of the Big Blocks Quilt Along.

You can sign up to the quilt along (even if you are reading this in the future!) here:


Fabric Requirements: Quarter Log Cabin Block

quarter log cabin fabric strips
Photo: Scrap Fabric Love

This block will be made with a starting square and then a series of pairs of strips. Each pair is made up of two strips of fabric that are the same (or very similar) in color. See graphic below.

Fabric requirements given are for 1 quarter log cabin block – to make a set of 4 just cut 4 where it says (1).

  • (1) 4.5″ Square to start with – mine was white with a small polka dot print.
  • Pair 1: (1) 4.5″ square; (1) 4.5″ x 8.5″
  • Pair 2: (1) 2.5″ x 8.5″; (1) 2.5″ x 10.5″
  • Pair 3: (1) 2.5″ x 10.5″; (1) 2.5″ x 12.5″
  • Pair 4: (1) 4.5″ x 12.5″; (1) 4.5″ x 16.5″
  • Pair 5: (1) 2.5″ x 16.5″; (1) 2.5″ x 18.5″
  • Pair 6 (1) 2.5″ x 18.5″; (1) 2.5″ x 20.5″. (OR if you want to make sure you aren’t cut short and you are happy to trim your block down make this final pair 3″ wide like I did!)

I cut my strips with my AccuQuilt Go Big Cutter and the die numbers I used were #55017 (2.5″ strips); and #55054 (4.5″ strips).

quarter log cabin fabric requirements
Photo: Scrap Fabric Love

TIP: Set your pairs out in the order you will sew them on from shortest to longest.

How to Sew a Quarter Log Cabin Block

Step 1: Sew Pair 1 to your starting square

To start take the 4.5″ starting square and the 4.5″ square from Pair 1 and sew right sides together with a quarter-inch seam.

Next, press your seams before sewing the longer strip from Pair 1 to the opposite side of your starting square. You should be sewing over the seam you just created.

See the sewing order graphic below or the video tutorial at the end of this post if it is unclear where to place your strips.

quarter log cabin sewing order guide
Photo: Scrap Fabric Love

TIP: You can chain piece 4 at a time (or more!) to make block construction faster as long as you have a way of keeping your pairs of strips organized so you don’t get mixed up!

Step 2: Continue Sewing Pairs

Repeat this pattern of sewing the short strip on first (same side as the previous short strip), followed by the long strip.

quarter log cabin block
Photo: Scrap Fabric Love

Your block should be getting bigger in one direction – as though the square you started with is increasing in size with each pair.

Continue sewing in this way until all your strip pairs are attached.

Step 3: Trim your Block to Size

If you have a large square ruler you can line it up to the edge of the 4.5″ square you started with and follow the diagonal line up the center to square up your block to 20″ square.

trimming quarter log cabin quilt block

If you don’t have a square ruler just use the lines on your cutting mat and the longest ruler you have to square up your block.

Finished Quarter Log Cabin Quilt Blocks

There are several ways you could orient your blocks to get different layouts for your quilt top. Below are a few options using four quarter log cabin blocks.

four quarter log cabin quilt blocks
Photo: Scrap Fabric Love
quarter log cabin quilt blocks layout option
Photo: Scrap Fabric Love
quarter log cabin quilt block layout
Photo: Scrap Fabric Love
quarter log cabin quilt block layout opiton
Photo: Scrap Fabric Love

How Many Blocks do I Need?

The great thing about big blocks like this is that you don’t need that many to start making a sizeable quilt.

Below are some examples of quilt sizes and how many blocks you will need. These measurements don’t include optional sashing and borders that would increase the size of your quilt.

  • Baby Quilt (39″ x 39″) = 4 Blocks.
  • Twin Quilt (39″ x 78″) = 8 Blocks
  • Lap Size/Throw Size (58.5″ x 58.5″) = 9 Blocks
  • Double Quilt (58.5″ x 78″) = 12 Blocks
  • Queen Size/King Size (78″ x 97.5″) = 20 Blocks

Below are two examples of quilt sizes with two different layout options. The quarter log cabin block is great because it can look so very different depending on how you lay it out.

quarter log cabin baby quilt
Photo: Scrap Fabric Love
throw quilt layout
Photo: Scrap Fabric Love

Quarter Log Cabin Block Video Tutorial

If the video does not appear below you can find it on YouTube here: https://youtu.be/9LlT_5T9cig?si=0w_5cS35LpiH_Yo_

If you enjoyed this block you will probably like the previous block from the Big Block series – the Rail Fence Quilt Block!

Here are some other posts you might like: