How do I size designer clothing I cannot try on?

Work from garment measurements, not size labels. Independent designer sizing is not standardised, and the same numeric size varies significantly between labels — so find the brand’s own chart, and where it lists flat garment measurements (bust, waist, hip, length) compare them against a garment you already own that fits the way you want. Note the fabric: anything cut on the bias, or with no stretch content listed, is far less forgiving of a near-miss. Check where the piece is made and whether the chart is in US, UK, EU or IT sizing, because the conversion is where most errors happen. Then check the return window and whether sale items are excluded before you order two sizes — some brands we cover do not accept the second one back.