Britain weighs people in stone — 14 pounds to the stone — a unit Americans have mostly met only in period dramas, while the medical world everywhere records kilograms. This converter handles the full British format: enter whole stone in the Stone (st) box plus any leftover pounds in the Extra Pounds (lb) box, and the Kilograms (kg) readout does the combined math. The formula folds both inputs together — (stone × 14 + pounds) × 0.453592 — so 11 stone with 0 extra pounds becomes about 69.853 kg, and the schema's 10 st 7 lb example lands at about 66.678 kg. The Total Pounds (lb) box shows the intermediate step (147 lb for that example), which is handy when a US doctor's form asks for pounds and your UK records say stone. One stone alone is 6.35029 kg, the figure worth memorizing. Fitness apps with British users, expats translating their records, and anglophiles decoding a novel's character description all end up here.

With the pre-filled defaults — Stone (st) 11, Extra Pounds (lb) 0 — the Stone to Kilograms returns Kilograms (kg) 69.8532, Total Pounds (lb) 154.0000. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.