Dance Top Picks

Quilting Blog

How to Sew a Traditional Jacob’s Ladder Block

To some quilters, traditional quilt blocks may seem stuffy and old fashioned. But when you make traditional blocks — like this Jacob’s ladder quilt block — with modern methods and fabric, they take on a whole new life.

Jacobs Ladder Block tutorial

How to make a Jacob’s ladder quilt block

When broken down into elements, this block is just small four patches and half-square triangles sewn together in a nine-patch style. 

What you need

layer cake

For this block, I used a 10″ square bundle of Boundless Flower Shoppe. For this quilt block, 10″ squares work well because we can cut the squares into smaller squares and strips.

four squares

Choose four contrasting 10″ squares. Fabrics that are too similar will not show the design of the block. The four patches and the triangles will not show up if the fabrics blend.

Cutting directions

Step 1:

Cut strips

Layer a light fabric square (my blue dots) and a dark fabric square (my green print) right sides together. Cut each of the two squares into four 2½”-wide strips. We will only use 3 sets; you can discard the fourth strip set or use it for another block.

Step 2:

cut triangle strips

Layer the remaining two squares (my red floral and white print) right sides together. Cut two 4½” strips from each of the fabrics. Discard the extra fabric.

Step 3:

ruler placement for cutting triangles from stripsrotate the ruler for cutting the second triangle

Use a 45-degree ruler to cut 2 triangle sets from each of the strips: Cut a triangle from the end of the strip, rotate the ruler, and cut a second triangle.

cut the triangles

Repeat with the second strip. 

That’s all the cutting! You should have 3 strip sets and 4 triangle sets.

Sewing instructions

Take all of the fabric pairs to the sewing machine, keeping each piece with it’s pair. 

Step 1:

Using a ¼” seam allowance, chain piece the triangles, sewing on the longest edge. Sew all of the units one after another and clip the threads once all of the units have been sewn.

Step 2:

trim the points

Trim the points off the corner of the triangles, as shown above. This prevents bulk at the seam intersections and increases accuracy.

Step 3:

press to the dark side

Press the half-square triangles open, with the seams toward the darker fabric. Pressing toward the darker fabric prevents seam allowances from shadowing through.

Make a total of four half-square triangles that measure 4½” each.

Step 4:

Sew the long strips together lengthwise (along one of the long edges) using a ¼” seam allowance. Press the seams toward the darker fabric.

Step 5:

sewing four patches

Layer two of the sewn strip units right sides together, with opposite fabrics facing. The seams should nest together.

Cut the layered strip sets every 2½” to make four units. 

Step 6:

cutting third strip set

Cross cut the third strip set into two 2½”-wide units. Use these to make the final four patch. Discard the rest of the strip set (or use them for another block).

Step 7:

finished four patch

Layer two of the units right sides together, matching opposite fabrics. Sew together along the long edge, using a ¼” seam allowance. Press the seams open. Repeat until you have 5 four patches, each 4½” square.

Assembling the block

Step 1:

block sewing layout

Arrange the blocks as shown, in three rows of three. Take care to line up the triangles with the dark sides toward the center, creating a line with the seams.

All of the four patches should be turned the same direction as well. The green is in the upper right corner of each four patch. 

Step 2:

sew the rows

Sew the blocks into three rows of three blocks. Press the seams toward the four patch blocks. 

Step 3:

Jacobs ladder block

Sew the three rows together and press the seams toward the middle row. This block will be exactly 12½”. If it is not, check your seam allowance, cutting or pressing. There should be no trimming needed.

Madison Park Fabric

Our Favorite Pre-Cuts

Find the perfect traditional or modern precut quilting fabrics for your next project. You’ll love our array of styles and hues from top designers. Browse Fabric


Karen Fletcher

I like the quick block. However, it would be good to see how to arrange for projects such as quilts or table runners.

Terrie Springman

What a beautiful block! What are the fabric requirements for different size quilts using this pattern? Do you have pictures of a completed quilt?


your individual pieces are not squared up.

Wendy Rubbo

I’d like to see this block as a quilt. I’m trying to find a pattern for something I saw online and this block may be the one.


Leave a Reply

Your email address will not be published. Required fields are marked *

Leave a Reply