Pattern grading is the process of creating additional sizes from a sample size. Typically, a middle-sized pattern is used as the base sample size, and it is graded up or down for larger and smaller sizes. This can be done manually or digitally using digital pattern making software.
If you’re a technical designer working in the fashion industry, having knowledge of how to grade garments is absolutely essential, as it allows you to scale a base pattern throughout a size range while maintaining the correct proportions and fit. And while pattern makers are in charge of altering the actual pattern pieces, the technical designers are in charge of creating the graded measurements specs that pattern makers will be basing the pattern iterations on.
In my 15+ years of experience working in the fashion industry, I’ve worked with technical designers to develop graded measurement specs for hundreds of garments ready for production. While there’s no one-size-fits-all approach to grading garment sizes (and it takes some time to learn by doing!), we’ll cover foundational knowledge for grading.
Table of Contents
Pattern Grading Methods
Traditional Pattern Grading
Patterns can be graded manually by shifting the pattern pieces by a measured distance to create new sizes. This can be accomplished through methods such as slash and spread or pattern shifting.
Slash and Spread Method
The slash and spread method involves cutting the pattern along specific cut lines and spreading or overlapping the pieces to create larger or smaller sizes. Depending on the pattern shape, pattern makers need to strategize at which points to cut and make sure all components of the garment are graded without causing distortion. Here’s a good video reference of how the slash and spread grading method works.
Pattern Shifting Method
Pattern shifting is another manual grading method where the pattern is traced and moved up, down, left, or right by a set distance to create new sizes. Some traditional pattern makers make use of a grading tool to do this, like how you would see in this basic bodice grading video.
If you’re eager to learn more about traditional pattern grading, these books are a great place to start:
- Professional Pattern Grading for Women’s, Men’s, and Children’s Apparel by Jack Handford
- Grading Techniques for Fashion Design by Jeanne Price and Bernard Zamkoff
- Concepts of Pattern Grading: Techniques for Manual and Computer Grading by Kathy K. Mullet
While manual pattern grading is still utilized by a lot of pattern makers, it is generally more suitable for home sewing, tailoring, and small-scale production due to the time, effort, and expertise required. Large-scale production typically employs digital pattern grading methods for efficiency and precision.
Digital Pattern Grading
Digital pattern grading is the go-to method for mass production in the fashion industry. Using digital pattern making software, you can automatically adjust your pattern sizes according to preset rules, saving tons of time and effort. You’re also not locked into automatic grading, digital pattern making tools gives you the flexibility to modify grading rules or get hands-on and manually adjust sizes digitally. This approach not only speeds up the grading process but also makes it easier to manage and share patterns.
If you’re curious about digital pattern making, I’ve put together a guide of the best pattern making software out there, including Gerber Accumark, Optitex, CLO, and more.
Check Point: Before diving into garment grading, it’s crucial to understand key concepts like Points of Measures (POMs) and garment specs. If you’re new to these topics, you can hop onto my Ultimate Guide to POM’s and How to Spec a Garment.
Grade Rules and Tolerances in Garments
What are Grade Rules?
Grade rules determine how much each Point of Measurement (POM) should increase or decrease between sizes. These increments are reflected in the measurement specification sheet or graded specs sheet, a chart outlining the dimensions of every POM in a garment for each size.
Grading rules are not set in stone and can vary depending on factors like garment style, fabric type, and target demographics. As a result, many fashion brands utilize grade rule libraries, which are collections of pre-established rules tailored to different garment types and sizes. Even then, designers can still tweak them to align with specific design goals and preferences. But if you’re a freelance fashion designer or technical designer, you might not have access to grading rule libraries.
Crafting accurate grade rules requires a deep understanding of the human body measurements and how they change in size and shape per size range. It’s not merely a matter of adding or subtracting measurements uniformly. For instance, grading rules for raglan sleeves differ from those for set-in sleeves due to structural differences. Technical designers must carefully consider each garment segment and its impact on fit.
Key considerations when developing grade rules include:
- Target customer’s body shape and proportions
- Garment style and fit
- Fabric type and characteristics
Let’s use my t-shirt graded specs as an example:
You’ll find that each POM in the table is graded in different increments, ranging from 1/4” to 2”. For example, if you look at the measurements of the front neck drop, you’ll see that the measurement becomes larger by ¼” as the size goes up – from 3 ½” for XS, 3 ¾” for S, 4” for M, and so on. Wider measurements like the chest width increase by 1” on the graded spec sheet table, but in reality, this measurement is multiplied by 2x as these are flat measurements. So, the 19” chest width on XS is actually 38” when measured in full, and 20” on the S is 40” in full, and so on.
These increments determine how much each part of the garment should increase or decrease in size based on the expected changes in body proportions.
Smaller areas like parts of the neck are graded in increments of 1/4” to 1/2”, while larger areas like the shoulder and chest are graded in increments of 1” to 2”. Certain components like the back neck drop remain ungraded, as the size change in this area is often negligible. Similarly, elements like collar band width that are meant to be consistent throughout sizes are ungraded.
1/4” increment:
- Neck Width
- Front Neck Drop
- Sleeve Length
1/2” increment:
- Across Front
- Across Back
- Armhole Straight
- Armhole Curve
- Sleeve Opening (*1/4” in flat measurement)
1” increment
- Shoulder Width
- Body Length
2” increment:
- Chest Width (*1” in flat measurement)
- Body Sweep (*1” in flat measurement)
*Measurements are recorded in flat measurements, meaning some of the width measurements including the ones marked in * are recorded in half size.
Pro Tip: Garment grading increments usually reflect the size changes within a brand’s internal size chart. For example, if your size chart increases the waist measurement by 2 inches as the size goes up, ensure your grading follows the same size difference. If you don’t have an internal size chart for your brand yet, check out my guide on the different size charts in the fashion industry.
What are Tolerances?
Tolerances represent the acceptable range of deviation from specified measurements in the graded specs. Achieving 100% precise measurements in every garment is nearly impossible due to factors like fabric stretch, sewing techniques, and variations in manufacturing processes. Tolerances are established to accommodate these variables realistically while still maintaining acceptable levels of accuracy.
This is typically done by setting upper and lower limits around the base measurement for each size. For example, if the base measurement for a particular POM is 30″, you might set a tolerance of plus or minus 0.5 inches, meaning the acceptable range would be 29.5″ to 30.5″. Again, similar to grading rules, there are no set rules for tolerances and their extent depends on the brand’s quality standard levels.
In my T-shirt graded specs, I’ve opted for tolerances equal to half of the grading increment. That’s one way to do it, but some brands may specify tolerances as a percentage of each measurement, say +/- 3% of each POM.
Additional Examples of Graded Specs
Mastering grading rules is an on-going process. The more graded specs you create for various types of garments, the more you learn and refine your skills. To help you out, I’ve compiled additional examples of graded specs below:
Hoodie Graded Specs and Tolerances
Jeans Graded Specs and Tolerances
You can also snag my FREE full tech pack templates on the three garment samples above which include the graded specs for all sizes:
