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Why are some indie patterns graded so “jumpy”?

Have you ever used a pattern that “jumps up and down” in the grading between sizes?  Recently I was trying a pattern that had grades jumping between 1/4″, then 1/8″, then 3/8″:


Since I come from an industrial background where this would never happen, it  makes me wonder not only why this is, but how did it happen? Grading is a simple matter of sliding the master pattern up-and-over by a consistent measurement “rule”, so why are there inconsistencies?  After all, garment industry patterns have consistent grading, Big Four paper patterns have consistent grading…..the grade may be smaller within the smaller section of sizes, and larger within the larger sizes, but never jumping up and down. Why does this happen so often in indie pdf patterns? I have a theory…..

First of all, why this is even important? If patterns are made for the home-sewist who is making a single garment, not making a size-range to sell, it is less critical that the grading be accurate than it would be for mass-production.  I’ve read many a FB post where home-sewists say they could not care less if a pattern is graded correctly because they are only making one outfit for one person, and I understand that…especially if it’s for a person who has finished growing, and doesn’t gain or lose weight.

But if you sew for a growing child, or for siblings (and you want their clothes to be proportionate) it does matter. And for those of us who sew to sell, having consistency in the full size range is important.

So how does grading work? I’ve talked before about the different systems used for grading. Whether grading is done by hand:


….or using a $20,000 Gerber machine/AccuMark® or Optitex  CAD software professional system, the theory is the same: from a fit-approved pattern in a middle size, the pattern is shifted up-and-over on the X and Y axis according to the established grade rule to create the next size larger …or down-and-over to make the next size smaller. The shape remains the same, the angles remain the same, the only thing that changes is the size.


But now many indie designers draft patterns directly on a computer screen using generic software such as Illustrator:


Instead of sliding a master pattern, the designer can plot measurement points on the screen directly from the size chart. Unfortunately, the further away the designer gets from the basics of drafting with a French curve and hip curve, the greater the possibility that the resulting product can be inconsistent in shapes and angles (which I’ve discussed many times).  But what about the inconsistencies of measurements (not shapes) in grading ? Where is that coming from?

I have an idea: there may be a possibility that some grading is done with the size chart taking priority over the grade rule.

Grading patterns is a process aimed at fitting the largest variety of people adequately.  It is the opposite of couture, which aims to fit one person perfectly. Commercial pattern grading involves compromise; it doesn’t let perfection (for one person) dominate over the good (of the most people):


If pattern grading aims to fit the widest variety of customers, this involves compromise, including the connection between the Size Chart and the pattern grade. For example, look  at this portion of the above graded pattern piece, just sizes 1/2 to toddler 4:

IMG_0475 copy

Here is the BODY SIZE chart info for those sizes (in descending sizes to match the pattern piece), and the corresponding grades between sizes, and the quarter-grades (total chest circumference divided by left/right/front/back):


That shows how the pattern grade jumps around from 1/4″ to 1/8″ to 3/8″ to 1/4″. The graded pattern does correspond to the size chart, and the size chart itself is fine: kids often do grow more from size 1 to 2, than they do between 2 and 3.

However by following the size chart so literally, there’s no garment to fit the child whose size is halfway between size 1 and 2. The pattern doesn’t fit the largest number of customer adequately. The perfect has become the enemy of the good.

An apparel production company would smooth the grades evenly, with a 1/4″ grade for every size:


Now this part may be confusing but here goes: a garment manufacturer might keep the original standard SIZE CHART as before, and STILL grade this style evenly between all sizes:


Does this mean that the size 2 garments are going to slightly tight, comparing garment to size chart? Yes. This is a compromise made to reach the goal of fitting the most number of customers, with a consistent grade between sizes.

The  bottom line is this: if a pattern designer is marketing to home sewists who are going to make single garments, then having a smooth grade between sizes may not matter. It would be nice to know, however, which patterns are suitable for home-sewing only…and which can be used to create a smoothly graded set of garments for selling.

Postscript 2/20: I received a question about why a size chart (especially for such small sizes) have a 1 and 1/2″ grade between sizes. Two reasons:

  1. Children may grow quite a bit between sizes 1 and 2, and many patterns have an in-between size (18 months), but in a loose-fitting garment like this, possibly the designer decided to skip the 18 month size.
  2. Size charts are often rounded to the nearest half-inch, for the consumer’s sake (it’s difficult for some people to measure a body to the quarter-inch).  So while the designer’s “in-house” size chart (for manufacturing) might have a consistent 1 and 1/4″ grade between sizes, the compromise is to make one of the grades 1″ and the next one 1 and 1/2″ on the published size chart (for the manufacturer’s website, or on hang-tags).


Happy Sewing!  Best regards, Janet



  • JustGail

    But why does the size chart have those measurements? I can’t think of why you’d have a 1 1/2 inch gap between size 1 & 2, a 1/2 inch gap between size 2 & 3, but 1 inch between the others. I looked back at the post about different grading systems, and saw that the Hummingbird pattern had similar odd (to me at least) uneven steps between sizes.

    Is there some industry standard thing going on that as a home sewer, I’ve never learned?

  • [email protected]

    My guess is that there was really a 1 and 1/4″ grade between sizes 1 and 2 and 3, and for the sake of customer’s measuring skills, the designer rounded one grade up and the other down. It’s just easier for most people to measure to the half-inch. The Hummingbird grading makes no sense to me at all: by the time you get to the larger sizes, the garment measures LESS than the body size chart. They must be counting on the stretch across the back to compensate, but if you look at the tester photos, the larger the model, the skimpier the bodice. And yes, Hummingbird grading is jumpy as well.

    As far as an industry standard, in adult sizes it’s standard to have a 2″ grade between bust sizes, but in children’s wear there are no such standards. Plus with the sizes being smaller, it’s difficult to use fractions of inches when customers don’t have good math skills. That’s why many companies publish a rounded-to-the-half-inch size chart, but use a smoother size chart behind the scenes.

  • Betsy

    They used ASTM standards as a grade rule and then had a separate size chart for body measurements, not understanding they must correlate. The hard part is trying to explain why this is not a good idea.

  • [email protected]

    Do you suppose that they think it doesn’t make a difference, if the customer is mainly the mom sewing a single individual item for her daughter? It seems that many pdf patterns these days are not geared towards making a graded size range of garments.

  • Bernadette Reinecke

    I’m going to make an assumption that designers do this because they want a set amount of ease in each size. The size charts are often based off of the ASTM standards which is not even between sizes. If they base their grading off of a set amount of ease per size, I can see how this would show up as “jumpy” grading.

  • [email protected]

    I totally get that, this way they can say “all sizes have 1 1/2″ ease” or whatever. I’m just comparing to the process generally used in mass production, where the GARMENTS are graded to a standard rule, even though the ASTM is not “graded” to a standard rule.

    And then there are the patterns where the jumpy grading simply makes no sense (example: the dress lengths in my previous post). That is beyond my understanding.

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