Does Forever 21 Run Big or Small? Sizing Guide & What to Buy

Forever 21 has built a global reputation for affordable, fast fashion that captures trends at lightning speed. Whether you're buying basics, statement pieces, or accessories, there’s one recurring concern many UK shoppers face:

Does Forever 21 run big or small?

And how do you find your right size when everything varies so much?

In this guide, we break down Forever 21’s sizing tendencies, explore which categories are trickiest, and show you how Tellar.co.uk takes the guesswork out—by matching your body to the right size in 1,500+ brands, including Forever 21.

Forever 21 Sizing Overview: What You Need to Know

Forever 21 originated in the US, and its sizing system is American-based—meaning their Small/Medium/Large labelling and numerical sizes (US 2, 4, 6, etc.) don’t always translate clearly for UK shoppers.

In general:

Forever 21 clothing tends to run small, particularly in dresses, crop tops, and tight-fitting items
Fabric quality and stretch can vary, meaning some pieces run true to size, while others feel undersized
Items like loungewear, joggers, and oversized tees often run slightly large or relaxed

Does Forever 21 Run Small or Large?

Based on data from Tellar.co.uk’s real-user fit database, here’s what we’ve found:

Tops & Bodysuits: Often run small, especially across the bust and shoulders
Dresses: Vary significantly, but typically run small in fitted styles
Jeans & Trousers: Inconsistent sizing, especially in waist-to-hip ratios—many users need to size up
Loungewear & Jumpers: Often true to size or slightly generous
Swimwear: Runs small, particularly bikini tops

Overall Verdict:

Forever 21 runs small in most categories. UK shoppers should expect to size up, especially in tight or structured pieces.

Forever 21 UK Size Conversion Guide

US Size	UK Size	Notes
0	4	Very small—may not fit true UK 4
2	6	Often snug at waist and hips
4	8	Typically fits like a UK 6
6	10	Close to UK standard fit
8	12	May feel tight in some styles
10	14	Some relaxed items fit true

Rather than convert manually, you can instantly find your Forever 21 size using Tellar.co.uk.

What Real Shoppers Say About Forever 21 Fit

“Forever 21 crop tops are cut super small—I always go up a size, especially if it's a non-stretch fabric.”
– Mia, Birmingham

“Their joggers and tees fit true to size, but jeans are really inconsistent. Tellar helped me find the right fit the first time.”
– Amira, Manchester

“I love their style, but sizing always confused me until I used Tellar. Now I know exactly what works.”
– Jade, London

You don’t need to guess or return again. Tellar.co.uk gets it right based on your body measurements.

How Tellar.co.uk Helps You Shop Smarter

Tellar.co.uk is the UK’s most advanced sizing tool—matching your real measurements to the exact size in brands like Forever 21, Zara, H&M, and 1,500 others.

Why it works:

✅ Free and easy to use
✅ One-time setup with your measurements
✅ Works in cm or inches
✅ You get a FREE measuring tape
✅ Compatible on mobile or desktop
✅ Stay logged in and check size anytime you shop

→ Create your free profile now

How It Works – Just 30 Seconds

Go to www.tellar.co.uk/create-profile
Enter your chest, waist, and hip measurements
Choose your preferred unit: inches or centimetres
Tellar shows your perfect Forever 21 size
Return anytime via login page to update or check new brands

No more awkward returns. Just the right fit every time.

Why Forever 21 Sizing Is So Inconsistent

Fast fashion brands like Forever 21 often work with multiple suppliers, leading to major inconsistencies across:

Fabric stretch
Manufacturing countries
Batch variation
Cut and style evolution from season to season

That's why two size 8s might not fit the same—even from the same store.

Tellar solves this by comparing your measurements to each brand's specific cut data, not just generic size charts.

Top Forever 21 Items Worth Buying

Forever 21 is ideal for certain wardrobe staples and trend-led pieces. Here’s what to go for (especially when you know your correct size):

1. Oversized T-Shirts

High-value basic. These tend to run true to size or generous—great for layering.

2. Denim Jackets

Cut slim but wearable. Size up if you want room for jumpers underneath.

3. Workout Leggings

Affordable, trendy, and comfy. Some run small at the waistband—Tellar helps match you to the right stretch level.

4. Basic Bodycon Dresses

Staple for parties or layering. Typically run small—measure before buying.

5. Swimwear & Lingerie

Size-specific pieces where getting it right really matters. These run tight, so use Tellar’s fit suggestions to avoid misfires.

Love Forever 21? You’ll Also Shop…

If Forever 21 is your go-to, you likely shop these brands too:

PrettyLittleThing
Boohoo
Missguided
New Look
Zara

Tellar.co.uk works for all of them—so you’ll get your exact fit, every time.

→ Check your size in 1,500+ brands now

Follow Tellar.co.uk for More Fit Tips

Get sizing hacks, fit comparisons, and fashion content direct from the experts:

Instagram: @Tellarsizing
Facebook: TellarSizing
Twitter/X: @Tellar100
Pinterest: TellarSizing

Conclusion: Does Forever 21 Run Big or Small?

Most Forever 21 pieces run small, especially structured and trend-led styles like crop tops, dresses, and denim. Loungewear, tees, and basics may run more generous.

To avoid inconsistency, use Tellar.co.uk to check your true size in seconds—not just for Forever 21, but across your entire wardrobe.

Final Call to Action

💡 Want the right Forever 21 fit the first time?

✅ Create your free Tellar profile
✅ Receive your free measuring tape
✅ Works with UK/US sizing, cm or inches
✅ Access 1,500+ brand size matches
✅ Stay logged in for instant results before every purchase

Find your size in 1,500+ brands real-time. It’s free & easy.

→ Start now at www.tellar.co.uk