Free, private, no signup: this page (and every calculator on this site) runs entirely in your browser. Nothing you enter is stored.
How UK Sizing Actually Works
UK bands are measured in inches exactly like the US, but the cup ladder keeps distinct letters (E, F, FF, G, GG, H) instead of repeating D’s.
If you’re ordering from a UK retailer while living somewhere else, the band number needs no conversion. Only the cup letter does, once you’re past a D.
Convert Your Size
Use the calculator above to see your size across all 7 systems this site supports, UK included. If you already know your size in another system, enter it into the Global Bra Size Converter instead of doing the math by hand.
Getting an Accurate Starting Point
Getting this right starts with the measurement, not the conversion table. See How to Measure for the technique this tool relies on, then check the Sister Size Calculator if the first size feels slightly off.
A Worked Example for the United Kingdom
Say your underbust measures 28 inches and your bust measures 32 inches. A US 28D.
Converted to the United Kingdom’s system, that becomes roughly 28″ D using the formula above. Run your own numbers through the calculator on this page rather than eyeballing the conversion. Small rounding differences near a size boundary can shift the result by a full cup letter.
Shopping Locally vs. Importing in the United Kingdom
British high-street retailers are generally good about keeping a full run of sizes in-store, so a converted UK size is usually worth trying on before ordering anything online.
Common Sizing Mistakes Shoppers Make in the United Kingdom
UK shoppers often assume a DD-and-up cup letter maps directly onto a US letter of the same name, when in fact the two scales diverge noticeably past that point.
Another UK-market slip is measuring over a t-shirt or thick top, which adds enough bulk to shift both the band and bust numbers by a meaningful margin.
A Note on Retail Fitting in the United Kingdom
UK department stores are generally well set up for walk-in fittings, and staff will usually re-measure on the spot rather than relying on a self-reported number.
Buying From the UK If You’re Not Based There
UK retailers frequently ship across Europe with relatively short delivery times, and post-Brexit customs rules mean it’s worth checking whether a specific retailer handles duties at checkout or leaves that cost for you to pay on arrival.
A Long History of In-Store Fitting Culture
The UK has one of the longest-standing traditions of free in-store bra fitting services among English-speaking markets, which is part of why UK sizing conventions are often treated as a reference point by other English-speaking countries.
Ordering From UK Retailers Abroad
International shoppers ordering from UK sites should double check whether a size chart shown is the retailer’s own UK-based chart or an auto-converted regional one, since some sites localize sizing labels for visiting international traffic.
Return Policies Are Generally Shopper-Friendly
UK consumer protection standards tend to make returns and exchanges straightforward for online lingerie orders, which takes some of the risk out of ordering a size you’re not fully certain about.
