While testing my new #justinpants pattern, going live in a few days (February, 10th), I noticed a lot of sewers can properly align notches on a straight seam (read horizontal or vertical, like side seams on a shirt), but explaining how to match notches on a curved or slanted seam is totally different.This made me think of writing this post!
First of all:

What are notches?

In a pattern, notches are small marks (usually black triangles or short straight lines, perpendicular to the cutting line), that help the sewer to align two pieces of fabric properly, so the seam will happen right where it has to be. This way the two pattern pieces will fit together perfectly.

Let’s take a closer look:

This two pattern pieces must be sewn together, at the seam line, matching the notches.Serger Pepper - Notches - How to use them 2Place them one on top of the other right sides together (RST), aligning the raw edges; make sure the two notches are in the same exact spot.

Serger Pepper - Notches - How to use them - align on straight seams

Now, sew along the seam line, open the seam allowances and check if your notches are matching… perfect!

Serger Pepper - Notches - How to use them - yess they match 2

This can sound obvious and redundant to almost any sewer, but what happens when they’re put on a slanted/curved seam? Do I have to match notches at the cutting line (the raw edges)?

My answer to this question is a huge resounding No-No!!!
Notches are put at the cutting line so you can transfer them easily to the fabric, but then you have to match fabrics at the seam line which is actually one seam allowance width in, on your pattern piece!

If you match notches at the raw edges, you’ll end up with a distorted/goofed garment!

How to use notches on a slanted (or curved) seam

I am using my new pattern (coming soon) colorblocked seams, for a real life example: the left side illustrations present a slanted seam, the right side ones are for a curved seam.

Identify the seam line, by measuring one seam allowance’s width in from the raw edge (perpendicularly to it) and trace it with a marking tool or hand basting it (on this pattern’s s.a. are 1/2″).

Serger Pepper - Notches - How to align a slanted curved seam

Identify a point on the seam line (point #1), by tracing a straight line perpendicular to the cutting line and that goes through the triangular notch tip and meets the seam line.

Repeat for the corresponding pattern piece (point #2).

Serger Pepper - Notches - point 1 and 2


Match each point #1 with the corresponding point #2, RST and pin them together.

Serger Pepper - Notches - pin together points 1 and 2

Now, the only thing left to do is to “connect the dots”: pin together the rest of the seam line, on both sides of each notch, until you reach the end of the fabric.

Beware: You should be ending with ear dogs at both ends: who cares? You’ll trim them out when you’ll sew the crossing seam!

Serger Pepper - Notches - ear dogs

Now: sew that seam, backstitching at each end.

Look at it from the wrong side of the fabric, to see if notches are perfectly pointing to each other!

Serger Pepper - Notches - How to use them - yess they match again

No more out-of-shape garments: in no time you’ll master the how-to match notches on a slanted (or curved) seam. Pin this tutorial for future reference and take it out the next time you’re sewing a notched princess seam or anything similar.

Serger Pepper - Learn to use Notches - pin me