Is Oversized the Same as Sizing Up? A Factual Breakdown

No, “oversized” and “sizing up” are not the same thing—though they might visually appear similar to an untrained eye. The distinction lies in how the garment is designed vs. how it fits your specific body.

1. What Does “Oversized” Mean?

Oversized refers to the intended design of the garment. It's cut to have extra volume in key areas—shoulders, chest, sleeves, or leg width—while still preserving proportion and structure. The piece is engineered to look roomy on your usual size.

Key features of oversized clothing:

Dropped shoulders
Extended sleeves
Relaxed, boxy, or wide silhouette
Still fits correctly at neck/waist/hem so it doesn’t drown your frame

👉 An oversized shirt in size M is designed to look loose on someone who wears a medium—no need to size up to achieve the silhouette.

2. What Happens When You “Size Up”?

Sizing up means buying a garment in a larger size than your body requires. This can result in a looser fit, but it’s not the same as wearing an oversized piece.

Effects of sizing up:

Proportions are distorted: shoulder seams drop, sleeves over-extend, and necklines may gape
Waistbands or structured seams may sit incorrectly
The fabric may bunch or collapse unnaturally in places not designed for volume

While sizing up can be a temporary workaround for a looser look, it typically sacrifices intended fit, tailoring, and garment structure.

3. When to Choose Oversized vs. Sizing Up

Situation	Go Oversized	Size Up
You want a trendy boxy silhouette	✅ Yes	🚫 No—distorts the garment
You’re between sizes	🚫 No—might drown the frame	✅ Yes—if the smaller size is tight
You're layering thick pieces under	✅ Oversized works well	✅ Size up if layering under slim-fit
You want comfort for loungewear	✅ Oversized or size up works	✅ But avoid overdoing it

4. Technical Fit Insight from Tellar.co.uk

Oversized garments are meant to be bought in your true size—this is how designers maintain the integrity of the drape and silhouette. Sizing up a regular-fit item, by contrast, won’t deliver the same aesthetic.

To avoid confusion, use Tellar.co.uk’s Store Size Lookup Tool, which matches your body shape to the correct size in each brand, whether you're shopping COS, Reiss, Arket, or Mango.

5. Want More Help Choosing Your Size or Fit?

Explore Tellar's free, expert-written fashion hub:

✅ Bottom Line

Oversized = designed for a looser fit in your usual size
Sizing up = buying a larger size, often leads to poor fit

For best results, let Tellar.co.uk guide you to the right size in the right brand and cut—especially when shopping oversized vs. fitted styles.

Follow Tellar for more fit science and style guidance:

Instagram: @Tellarsizing
Twitter/X: @TellarSizing
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Pinterest: TellarSizing

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