Armhole and neckline grading rules

What you will learn

Understand how to grade the armhole and the neckline between sizes: how much the armhole deepens and widens, how neckline growth is split between width and drop, and why keeping alignment matters more than hitting the exact millimeter.

Before you start

It helps to know first how a pattern is graded in general (base pattern + grading table), because here we deal with a particular case: two open curves, not a closed outline like the bust or the hip.

Concept

Grading a pattern means moving each point on the outline by the distance a grading table gives, to generate the rest of the sizes without losing the shape of the piece. The armhole and the neckline differ from the bust or hip outline in one key way: they are not closed outlines, they are open curves that connect the front and back to another piece (the sleeve, the collar or a piping strip), and that connection has to keep fitting together in every size. That is why they are graded with their own logic, separate from the bust circumference: you have to decide how far each point moves —the highest point of the armhole, the side point, the base of the neckline— so the shape holds and the piece sewn to it still fits.

Lesson content

Armhole depth and width by size

There is no "official" figure for grading the armhole: each patternmaking school, each CAD system and each manufacturer builds its own table, and the number changes with the type of garment (a t-shirt does not grade the same way as a fitted blazer). As a rough guide:

Neckline width and drop

The neckline grows in two directions that are worked separately: the width (the distance between the two shoulder points) and the drop, meaning how far the neckline sits down on the chest or the back. A style may need more width and little drop, or the reverse, depending on the design of the garment.

Why the armhole does not grow like the bust circumference

The bust or chest circumference usually grows 4 to 6 cm per size, but that is a full circumference around the torso. The armhole is only the stretch of that circumference left free for the sleeve: if it grew in the same proportion, the sleeve cap would end up out of proportion to the back width and the sleeve length.

That is why the armhole grows far fewer millimeters than it would if the bust growth were shared out in equal parts. Much of that difference is absorbed by the ease of the garment, not by the armhole point: the armhole rule is defined separately, looking at how the sleeve cap has to turn out.

Alignment: the real priority when grading

Alignment means that the armhole point, the neckline point and the other references on the pattern (bust line, center front, side seam) stay lined up with each other from one size to the next, keeping the same proportion of the piece. It matters more than millimeter accuracy: a table with increments slightly different from another brand's works just as well if alignment holds, but a table with the right numbers applied without care for alignment ruins the grading.

Where you notice lost alignment most is at the notch: the mark that shows where the sleeve enters the armhole, or where the collar meets the neckline. If the notch ends up shifted, the sleeve or the collar stop matching, and the problem only shows up when the sample is sewn. To check, it is enough to overlay the sizes —on paper against a light, or on screen in CAD— and confirm that the notch followed the same line as the rest of the outline.

Practical example

The bust circumference might grow, for example, 5 cm per size (within the typical range of 4 to 6 cm), while the armhole of that same garment grows only a few millimeters. That large gap is not an error: most of the bust growth is absorbed by the ease of the garment, not by the armhole point.

Common mistakes

Grading the armhole in the same proportion as the bust circumference.: The armhole is only the stretch of that circumference left free for the sleeve: if it grows like the bust, the sleeve cap ends up out of proportion. Define it separately, looking at how the sleeve has to turn out.

Prioritizing an exact millimeter match with a reference table without checking alignment.: A table with slightly different numbers works just as well if alignment holds; a table with the "correct" numbers applied without care for alignment makes the notch shift, and the sleeve or the collar stop matching when sewn.

Modeltex tip

Modeltex digital patterns are delivered with the armhole and neckline grading rule already defined, with the full size range graded and approved with a sewn sample, so that work comes already solved.

Exercise

Take two consecutive sizes of a pattern (your own or a digital one) and overlay the front piece in the armhole and neckline area. Check whether the armhole notch follows the same line as the rest of the outline in both sizes: if you see that it shifted, that is where you lost alignment.

Frequently asked questions

What are the grading rules for the armhole and the neckline?

There is no single rule: each school and each CAD system builds its own table, but a common rough guide deepens the armhole by 5 to 10 mm per size and widens it by 3 to 7 mm, while the neckline grows 3 to 5 mm in width and 1 to 6 mm in drop, more at the front than at the back. These numbers are adjusted to each manufacturer's real measurement chart and validated with a sewn sample.

How much does the armhole deepen per size?

As a rough guide, 5 to 10 mm per size, a little more in the extreme sizes (3XL, 4XL). It is not a fixed number: it depends on the type of garment and on each brand's measurement chart, and it is best confirmed with a sewn sample.

How does the neckline grow from one size to the next?

In two directions: the width, 3 to 5 mm per size, and the drop, which usually grows more at the front (3 to 6 mm) than at the back (1 to 3 mm), because the volume that appears between sizes is concentrated at the front. These are rough values that each manufacturer adjusts to its own measurement chart.

Why doesn't the armhole grow in the same proportion as the bust circumference?

Because the bust circumference is a full circumference (it grows 4 to 6 cm per size, as a rough reference) and the armhole is only the stretch of that circumference left free for the sleeve. If the armhole grew in the same proportion, the sleeve cap would end up out of proportion; much of that difference is absorbed by the ease of the garment, not by the armhole point.

What is alignment, and why does it matter more than exact millimeters?

It means that the armhole point, the neckline point and the other references on the pattern stay lined up with each other from one size to the next, without drifting from the proportion of the piece. A table with slightly different increments works just as well if alignment holds, but a table with the right numbers applied without care for it makes the sleeve or the collar stop matching when sewn.

Is grading the armhole by hand different from doing it in CAD software?

By hand, you draw on guide lines and move each point with a ruler and set square, size by size, with a higher risk of losing alignment the more sizes the range has. In Optitex, Audaces or Gerber the rule is loaded once and the system generates the whole range; Modeltex patterns already come with this rule solved and the full size range approved with a sewn sample.

Summary

The armhole and the neckline are graded with their own logic, different from the bust circumference: the armhole deepens 5 to 10 mm and widens 3 to 7 mm per size, and the neckline splits its growth between width (3 to 5 mm) and drop, with more drop at the front than at the back. The exact numbers vary by school, CAD system and type of garment, but what can never fail is alignment: the armhole, the neckline and the other pattern references must stay lined up in every size.

Go back to the full course or ask the Modeltex Lab AI.