T-Shirt Sizing Guide for Clothing Brands: Oversized, Regular & How to Create Your Size Spec

t-shirt sizing guide for clothing brands — neatly folded t-shirts in multiple sizes

One of the most common complaints in streetwear brand communities: "My bulk order came back and the sizing is completely off." Shirts are too narrow, too short, or inconsistent between sizes.

This almost always comes down to one thing: the brand didn't provide a proper size specification to the factory. Here's how to get it right.

Understanding Fit Styles

Before you can write measurements, you need to decide on your fit style. The three most common for modern clothing brands:

Fit Style Description Typical Chest Width (M) Popular For
Slim / Regular Close to body, follows natural shape 19–20" Basics, workwear-casual
Relaxed / Classic Comfortable room, not tight or boxy 20–22" Lifestyle brands, versatile appeal
Oversized / Boxy Deliberately wide and dropped shoulder 24–28" Streetwear, contemporary fashion
Cropped Shorter body length, various widths Variable Women's, fashion-forward brands

Key T-Shirt Measurements You Must Specify

Every size spec should include these minimum measurements (in inches or cm):

Measurement Where to Measure Why It Matters
Chest Width (HPS) 1" below armhole, across front Primary indicator of how "big" the shirt feels
Body Length From HPS (high point shoulder) to hem Determines how much of the shirt tucks in or hangs out
Shoulder Width Seam to seam across top of back Critical for oversized/drop shoulder fits
Sleeve Length From CB neck to cuff Affects the overall proportion of the shirt
Sleeve Opening Circumference at hem of sleeve Affects drape and fit around the upper arm
Neck Opening Front to back neckline circumference Affects ease of wearing and visual appearance
Armhole Depth From shoulder seam to underarm seam Important for movement and fit feel

Sample Size Chart: Oversized Streetwear T-Shirt

Here's a reference size chart for a modern oversized streetwear tee (all measurements in inches):

Measurement XS S M L XL XXL
Chest Width 22" 23" 24" 25" 26" 27"
Body Length 27" 27.5" 28" 28.5" 29" 29.5"
Shoulder Width 19" 19.5" 20" 21" 22" 23"
Sleeve Length 8" 8.5" 9" 9.5" 10" 10.5"
Sleeve Opening 7" 7.5" 8" 8.5" 9" 9.5"
Neck Rib Width 0.75" 0.75" 0.75" 0.75" 0.75" 0.75"

Note: These are reference measurements only. Adjust based on your brand's specific fit aesthetic and target customer body type.

What Is Size Grading?

Size grading is the process of mathematically scaling measurements from one base size to create the full size run. For example, if your base size is M, grading means calculating how much larger L, XL, and XXL are, and how much smaller S and XS are.

Standard grading increments for oversized t-shirts:

  • Chest: +1" per size step
  • Body length: +0.5" per size step
  • Shoulder: +0.5–1" per size step

Some factories handle grading for you once you provide the base size measurements. Always confirm who is responsible for grading in your agreement.

US vs. European vs. Asian Sizing Differences

Different markets have different sizing conventions. Key differences to be aware of:

  • US customers typically prefer sizes labeled S/M/L/XL and expect generous measurements for each size
  • European customers may prefer more structured fits; EU size numbers (EU 48, EU 50) are also common
  • Asian markets typically run smaller — Asian factories may default to Asian sizing if you don't specify

Always specify that your size spec is for US/EU customers when working with Asian factories. This prevents one of the most common sizing mistakes — receiving garments that are 2 sizes too small for your target market.

Get Sizing Right With Storiginator

At Storiginator, we help every new brand develop a size spec that's right for their fit aesthetic and target market. We'll review your measurements, suggest adjustments based on our experience, and confirm fit accuracy at the sample stage before committing to bulk. Let's get your sizing sorted.

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