Brand Comparison · 2026

    ASOS DesignvsForever 21, Size Comparison

    Forever 21 tends to run smaller than ASOS Design. If you wear a Medium at ASOS Design, you may need a Large at Forever 21. For a measurement-based recommendation, use the fit checker.

    Quick Answer

    ASOS Design vs Forever 21 sizing, quick answer

    Forever 21 runs about one size smaller than ASOS Design. If you wear a Medium at ASOS Design, you'll likely need a Large at Forever 21. For an exact recommendation, build a free fit profile.

    • ASOS Design: fits true to size
    • Forever 21: runs small
    • If between sizes: size up at the brand that runs smaller, or use the fit checker below for a personalised recommendation.

    Brand guide

    Compare how ASOS Design and Forever 21 usually fit, where cuts feel slimmer or roomier, and which categories are most predictable.

    GENERAL BRAND GUIDANCE

    This is a general brand-level sizing summary, not an exact product recommendation. For your specific size, paste a product link into the fit checker.

    The Verdict

    ASOS Design sizing compared to Forever 21: ASOS Design fits true to size while Forever 21 runs small. Here is how the sizes translate.

    Forever 21 tends to run smaller than ASOS Design. If you wear a Medium at ASOS Design, you may need a Large at Forever 21. For a measurement-based recommendation, use the fit checker.

    ASOS DesignTRUE TO SIZE
    Forever 21RUNS SMALL
    ASOS Design logo

    ASOS Design

    TRUE TO SIZE

    True to size; Petite line runs very short

    Forever 21 logo

    Forever 21

    RUNS SMALL

    Fast fashion, runs small with very narrow cuts

    Category Match-up

    ASOS Design
    Forever 21
    Tops
    TRUE TO SIZE

    Varies by sub-brand. 'Design' line is typically true to size.

    RUNS SMALL

    Runs small with narrow cuts. Size up 1 as a general rule.

    Bottoms

    No data for ASOS Design Bottoms

    RUNS SMALL

    Jeans and skirts run small, especially through the hips. Size up 1.

    Dresses
    TRUE TO SIZE

    Standard fit is reliable, but 'Petite' runs very short.

    No data for Forever 21 Dresses

    Size Conversion Table

    Your SizeASOS DesignForever 21
    XXSXXSXS(Runs Small)
    XSXSS(Runs Small)
    SSM(Runs Small)
    MML(Runs Small)
    LLXL(Runs Small)
    XLXLXXL(Runs Small)
    XXLXXLXXXL(Runs Small)
    XXXLXXXLXXXL+(Runs Small)

    * Indicative only. For your personalised size at both brands,

    Common Questions

    Does ASOS Design run smaller than Forever 21?

    Forever 21 runs about one size smaller than ASOS Design. If you wear a Medium at ASOS Design, you'll likely need a Large at Forever 21. For an exact recommendation, build a free fit profile.

    Should I size up or down at ASOS Design vs Forever 21?

    Size up one at Forever 21 compared to ASOS Design. Forever 21 runs smaller, so if you wear a Medium at ASOS Design, try a Large at Forever 21, especially for fitted tops and tailored bottoms.

    If I'm a Medium at ASOS Design, what size am I at Forever 21?

    Since Forever 21 runs smaller than ASOS Design, a Medium at ASOS Design is roughly equivalent to a Large at Forever 21. Use the ThisFits fit checker for a recommendation based on your measurements.

    Does ASOS Design or Forever 21 fit differently by category?

    Yes, fit varies meaningfully by category. Tops can each fit differently than the brand's overall tendency suggests. See the Category Match-up section below for per-category guidance.

    Which brand is more accurate to its size chart, ASOS Design or Forever 21?

    ASOS Design and Forever 21 both publish official size charts, but real-world fit varies by fabric, cut and category. The ThisFits engine cross-references published charts with shopper fit reports across 197+ brands to predict your size in each.

    What if I'm between sizes at ASOS Design and Forever 21?

    If you're between sizes, Forever 21 tends to fit closer to the body, so trying the larger size first usually means fewer returns. Always confirm each retailer's return policy before ordering.

    More Comparisons

    Your Personal Size

    See your size in ASOS Design&Forever 21

    Build your fit profile once and see your likely size for ASOS Design and Forever 21, based on your measurements.

    197+ brands · Unlimited fit checks · No account needed

    Your size in both brands