Weight Converter

A weight converter changes a mass value from one unit into another — kilograms to pounds, grams to ounces, or stones to kilograms. The metric side (milligram, gram, kilogram, metric ton) scales by clean powers of ten, while the imperial side (ounce, pound, stone) uses historical ratios: 16 ounces to a pound, 14 pounds to a stone.

The bridge between the two systems is exact: 1 pound is defined as 0.45359237 kg. Everything else follows from that — an ounce is 28.3495 g and a stone is 6.35029 kg. Strictly speaking these units measure mass, not weight, but in everyday use (body weight, cooking, shipping) the terms are interchangeable.

This converter covers seven units — milligram, gram, kilogram, metric ton, ounce, pound and stone — and converts between any pair the moment you type a value. Body weight is the classic case: gym plates and US forms use pounds, most of the world uses kilograms, and UK bathroom scales still speak in stones (12 st 7 lb rather than 79.4 kg).

It is just as useful in the kitchen and the post office: converting a 12 oz package of ingredients to grams (340 g), checking whether a 5 lb parcel is under a 2.5 kg shipping tier (it is not — 5 lb is 2.27 kg, so it just fits under 2.5 kg), or translating a freight quote given per metric ton. Handy anchors: 1 kg ≈ 2.205 lb, 100 g ≈ 3.5 oz, and 1 stone = 14 lb exactly.

All math happens in your browser with exact conversion factors — nothing is sent to a server.