A US size 8 is a UK 12, an EU 40 and roughly a Japanese 11 — but only approximately, because brands vary their own charts on top of the regional standard. The only reliable method is to measure yourself and compare to the brand's own chart, not a generic conversion table.
Measure yourself first
Bust/chest, waist and hips in centimetres, taken over light clothing, beat any size label.
Use the brand's own chart
Generic conversion charts are a starting point only — always check the specific brand's measurements page.
