Sizing across US, UK, and EU brands is notoriously inconsistent — a US size 6 can land anywhere from an EU 36 to a 38 depending on the brand’s own fit block. Skipping the conversion chart and measuring yourself directly is the single most reliable fix.
Three measurements to take once and keep on file:
- Bust/chest — measure around the fullest part, keeping the tape parallel to the floor.
- Waist — measure at your natural waistline, usually just above the belly button, not where your trousers currently sit.
- Hips — measure around the fullest part, typically 7–9 inches below the waist.
Why brand size charts still matter. Even with your own measurements, always check the specific brand’s size chart rather than relying on a generic US-to-EU conversion — fit blocks vary enough between brands that a universal chart will mislead you as often as it helps.
Reading reviews for fit clues. Look specifically for reviewer comments like “runs small” or “true to size” rather than just star ratings — fit feedback is usually far more useful than the overall rating when buying sight-unseen.
The verdict: five minutes with a tape measure saves more returns than any size-chart shortcut.
Why sizing varies so much between brands in the first place
Each brand builds its own “fit block” — a base pattern calibrated to its target customer’s average body — and there’s no single enforced global standard tying clothing sizes to specific measurements. This means a size label is really shorthand for “the customer this specific brand designs for,” not a fixed measurement.
A simple conversion starting point (with a caveat)
As a rough starting point only: US sizing generally runs about 2 sizes below UK sizing, and UK sizing runs roughly 2–4 sizes below EU sizing — but treat this purely as a starting search point, never a substitute for checking the specific brand’s own chart.
Measuring yourself accurately — common mistakes
The most common measuring mistake is holding the tape too loosely or pulling it too tight — the tape should sit snug against the body without compressing skin. For the most reliable numbers, measure directly against skin, first thing in the morning.
When to size up in specific categories
Structured items with less stretch are less forgiving of a borderline measurement than knitwear or jersey — when between two sizes, sizing up is the safer default for structured pieces, while knitwear can often be sized down slightly if you prefer a closer fit.
Frequently asked questions
Should I trust a brand’s own size chart over general conversion charts? Always — brand-specific charts reflect that brand’s actual fit block, while general conversion charts are, at best, a rough average across many brands.
Do shoe sizes convert as inconsistently as clothing? Less so — shoe sizing is somewhat more standardized across brands than clothing, though width can still vary meaningfully by brand.
International shipping and return policies — read before you buy
Given how unreliable sizing conversions can be, check a retailer’s return policy for international orders before purchasing anything you can’t try on first — some brands charge return shipping or restocking fees specifically for cross-border returns, which can turn a “good deal” into an expensive mistake if the size is wrong.
Body-adjacent measurements that matter beyond bust/waist/hip
For tailored pieces specifically, inseam length and shoulder width are worth measuring and keeping on file alongside the three core measurements — these are the two most common reasons a “correctly sized” structured piece still doesn’t fit quite right off the rack.
How sizing has shifted over time
Clothing sizes have drifted over recent decades (sometimes called “vanity sizing”), meaning an old size chart or a size you wore years ago at a different brand isn’t a reliable reference point today — always work from current measurements rather than a remembered size number. This drift also varies by brand and by country, one more reason a fresh measurement-based approach outperforms memory or old labels when shopping across borders.
Sizing differences between clothing categories
Even within one brand, sizing consistency can vary by category — a brand’s dresses and its trousers aren’t guaranteed to follow identical measurements, since different product lines are sometimes developed by different design teams or fit models. When buying multiple categories from the same brand for the first time, it’s worth checking the specific chart for each category rather than assuming one size carries across.
A note on children’s and petite/plus sizing
Children’s, petite, and plus-size lines typically use entirely separate sizing systems from standard adult sizing at the same brand, not simply a scaled version of the main chart — always check the specific chart for that line rather than extrapolating from a standard-size chart you already know.
No product link — this is a reference guide; link to it from product reviews where sizing questions come up.