Weight converters

About weight conversions

Weight and mass get used interchangeably in everyday language even though they mean different things to a physicist — on Earth the distinction rarely matters for shopping, cooking, or shipping, so our converters (like most consumer tools) treat "weight" conversions the way people actually use the word. Kitchen recipes list ingredients in ounces and pounds or grams and kilograms depending on where they were written; gym equipment and body-weight scales show kilograms almost everywhere outside the US; and shipping carriers bill by whichever unit is standard in the origin or destination country.

One especially easy mistake: a US ton (short ton, 2,000 lb ≈ 907 kg) is not the same as a metric tonne (1,000 kg ≈ 2,204.6 lb), and neither matches the UK long ton (2,240 lb). Freight quotes, vehicle specifications, and agricultural yield figures often state which one they mean only in fine print — our converters label the unit explicitly so you are not left guessing which "ton" a document is using.

Body weight conversions carry their own regional quirk: the UK and Ireland commonly report body weight in stone (1 stone = 14 pounds) rather than kilograms or pounds alone, so a figure like "11 stone 4" needs converting through pounds before it maps cleanly to kilograms. Medical dosing, meanwhile, is almost always in milligrams or grams internationally, and getting a decimal point wrong when converting is one of the more consequential unit mistakes possible — always double-check dosage-related conversions against the original prescription or label rather than relying on a mental shortcut.

When converting body weight or package weight for display purposes, rounding to a sensible number of digits is fine; for billing, nutrition labeling, or anything with a legal or financial consequence, use the full-precision multiplier shown on each converter page rather than a rounded rule of thumb like "just double the kilograms" (which overestimates pounds by roughly 10%, since the real factor is about 2.2046).

Use the converters below for everyday tasks — checking a recipe, comparing a gym plate to a kilogram equivalent, or converting a parcel weight before an international shipment — and see our weight units guide for a fuller breakdown of metric versus customary units and where each one shows up in daily life.

Related reading: Weight vs mass: kilograms, pounds, and ounces