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Understanding the difference between Alpha and Numeric Sizing for Clothing 

It is important to research and understand standard sizing methods for clothing before taking the next step to produce your line commercially.
The chosen sizing method will make or break your brand, especially if you are relying on a great fit for your product.

The standard size range used in apparel are:

-Alpha sizing

-Numeric sizing

The difference between alpha and numeric sizing is the grading.

Grading refers to pattern grading, meaning how much the pattern is increased or decreased to accommodate corresponding size.

Alpha Sizing

  • Size range named by letters such as XS, S, M, L. This lettering is mostly universal.

  • Size range for Petite target market group are marked as PS, PM, PL or for Plus Sizes 1X, 2X, 3X, etc.

  • Usually applies for knit clothing (i.e. active wear, knitwear, sportswear).

  • Alpha size range is used for T-shirts, Sweatshirts, Hoodies, Leggings, Active Tank Tops/Sport Bras and similar clothing items.

  • Alpha size range covers a wider range of body sizes. Standard equivalent to numeric sizing:

    X-Small-0 to 2

    Small-4 to 6

    Medium-8 to 10

    Large-10 to 12

  • Standard grading rule for Alpha Sizing:

    XS to L: 2” circumference between sizes (all around)

    L and above:2 1/2” to 3” circumference between sizes (all around)

  • Actual grade rule will depend on the specific brand’s clothing fit.

Numeric Sizing

  • US women’s wear sizing uses numbers such as 0, 2, 4, 6, 8, 10 and so on. European equivalent uses numbers more related to the actual body measurements such as 34, 36, 38, 40, 42 (European Size Chart for Women).

  • Numeric sizing is commonly used for clothing made of woven fabrics in specific fit important styles.

  • Clothing items include dress pants, shirts, structured jackets, fitted dresses and similar clothing items.

  • Standard grading rule for Numeric Sizing

    0 to 10- 1” circumference between sizes (all around)

    10 and above- 1 1/2” to 2” circumference between sizes (all around)

There is a reason the same type of clothing is sized differently and fit disproportionately from brand to brand. Vanity sizing is everywhere. Know of it!


best practices before settling on sizing method

  • Research your market and body shapes within that market. It is not an easy task. However, it will help you understand your customer and their needs for clothing sizing and fit.

  • Study your competition and their best-selling clothing styles. Is it a fit?

  • Research and understand the size range and grade rules for specific clothing style.

  • Learn more about fabric properties and weights.

  • Study your target customer and their likes and dislikes especially their fit preferences.