How ThisFits works.

ThisFits tells you what size to buy across brands before you check out. Every recommendation draws on four layers of sizing intelligence, combined in real time for the specific product you're considering.

Brand size chart data

We maintain structured size charts for every brand in our directory, currently 197+ clothing brands and 60+ shoe brands. These charts include bust, waist, hip, and height ranges for each labelled size, along with EU and UK equivalents where applicable. Charts are sourced from official brand sizing pages and verified against published garment measurements.

When you check a product, ThisFits matches your body measurements against the brand's chart for that specific category, tops, bottoms, dresses, outerwear, or shoes, and identifies the size range that best fits your proportions.

Community sizing signals

Size charts alone don't tell the full story. A brand might list a Medium as 36–38" chest, but community consensus says it runs a full size small. We aggregate sizing sentiment from Reddit fit communities, fashion forums, and review platforms to establish a sizing tendency for each brand: runs small, true to size, or runs large.

These tendencies are category-specific where data supports it, Zara tops may run differently from Zara denim, and are updated as new community data emerges.

Your measurements and preferences

When you share your height, chest, waist, and hip measurements, or even just your typical size at a few brands, ThisFits builds a fit profile that informs every recommendation. Fit preference matters too: if you prefer a relaxed fit, we adjust accordingly. The more data you add, the more precise the output becomes.

Product-specific analysis

When you paste a product URL, ThisFits reads the product page to extract the brand, category, available sizes, and any product-level sizing notes. This context is combined with the brand's sizing tendency and your profile to produce a recommendation specific to that exact garment, not just the brand in general.