Skip to content
Rebuilding civilization

Unit converters

Mass and weight

Grams, kilograms, tonnes, ounces, pounds, stones, apothecary grains and Castilian arrobas and pounds.

Equivalents

milligram—mg
gram—g
kilogram—kg
metric quintal—q
tonne—t
grain (apothecary)—gr
ounce (avoirdupois)—oz
pound (avoirdupois)—lb
stone—st
short ton (US)—ton US
Castilian pound—libra cast.
Castilian arroba—@

How it is calculated

The value is converted to kilograms and from there to every unit. 1 lb = 16 oz = 0.45359237 kg (exact by definition), 1 stone = 14 lb = 6.35 kg, 1 US short ton = 2000 lb = 907 kg, and 1 metric quintal = 100 kg.

Quick rule: kilograms × 2.2 ≈ pounds. Example: 70 kg × 2.2046 = 154.3 lb.

Keep in mind

  • The grain (64.8 mg) appears in old pharmacy recipes: the classic “5-grain” aspirin is 324 mg.
  • The Castilian arroba is 25 pounds of 460 g, about 11.5 kg; in Aragon and Catalonia the pound and arroba were different. The Castilian “quintal” was 4 arrobas (46 kg), not the 100 kg of the metric quintal.

See also

More tools in “Unit converters”