How to do a Quilting Seam Test

Are you struggling with the accuracy of your quilting seams? Do your blocks often come out short or too large? Well, 4-5 years ago I learned a little technique that greatly improved my quilting accuracy and I want to share it with you.

This little exercise — which I call the Quilting Seam Test — will improve your “muscle memory.” That’s the memory your muscles have in doing an activity. In this case, we are going to train our eyes and hands how to watch and feed the fabric through the machine so that we get an accurate 1/4″ seam. Over time, if done regularly, you will see results.


First, make a test block:

You will need a 1″ wide ruler and three 1.5″ x 3.5″ strips to make your test block. It should go without saying that you do want to make sure those strips are cut accurately. Accurate piecing starts with accurately cut pieces.

Making sure raw edges are perfectly aligned, sew two strips together along the long edge using a quarter-inch seam. Finger press those open.

Sewing test strips
Two test strips are sewn together along the long edge.

Align another strip along the raw edge of one of these strips and sew again with a quarter-inch seam.

Improve quilting accuracy by sewing test strips
Placement of 3rd test strip

Take your time and sew slowly. Be mindful of where your fabric is lining up with your presser foot. When you’re finished, press the seam open, then take a 1″ wide ruler, and lay it over the middle strip.

If your block is perfect, it should nest down between the strips on each side perfectly, with no wiggle room. Notice in the photo below that my test seams are a little too small. My ruler is not quite able to nest down in between the seams.

Using a ruler to test your sewing accuracy
Not quite right. Try again.

If it’s not perfect, try again, making note of whether your quarter-inch seam was too wide or too narrow. Make adjustments before you sew again: either move your needle slightly or adjust how you align your fabric to the presser foot.

Testing accuracy of quarter-inch seams
Ruler lays perfectly inside the test strip seams.

As your patchwork skills improve, also try to make sure that your strips line up perfectly at the top and bottom of your block.

Repeating this exercise every time you sit down to sew will improve your accuracy. For more detailed information and other patchwork tips, see my tutorial on improving patchwork accuracy.

Until next time!