The stone still trips people up
Most weight conversions are straightforward multiplications. The stone is the exception, because it is the one unit still in daily conversational use that almost nobody outside the UK and Ireland can convert on sight.
One stone is 14 pounds, or about 6.35 kilograms — and body weight is usually quoted as a compound figure like “11 stone 4”, meaning 11 stone plus 4 pounds, or 158 pounds, or 71.7 kg. The mixed-unit format is what makes it awkward: you have to convert the stones and the loose pounds separately before adding them.
Converting between systems
Enter a value and pick the unit it is in. The converter immediately shows the equivalent in every other supported unit — milligrams, grams, kilograms, ounces, pounds, and stones — so you can read across metric and imperial at a glance. Everything runs in your browser.
Metric and imperial together
Weight conversions come up constantly: following a recipe from another country, reading a body weight in a different system, checking a shipping limit, or logging gym progress. Because this tool shows all units at once, you never have to choose a single conversion direction — change the source unit and the entire list recalculates instantly.
Exact and reliable
The conversions rest on exact international definitions: a pound is exactly 453.59237 grams, an ounce exactly 28.349523125 grams, and a stone exactly 14 pounds. That makes the results precise, with rounding appearing only in the displayed number. For very large or very small values the converter switches to scientific notation so the answer stays readable. Nothing you enter is stored.