Arroba (Spanish) (@)

Spanish & PortugueseHistorical unit (no longer in standard use)Approximate value

25 libras, about 11.5 kg. A Castilian weight (and a liquid volume unit); the '@' sign descends from its abbreviation.

1 arroba (Spanish) = 11.502325 kilograms (approximately).

Approximate value. Standards for the arroba (Spanish) varied by place and period, so this converter uses the most commonly cited value. Treat results as estimates, not exact figures.

About the arroba (Spanish)

Arabic ar-rubʿ, meaning a quarter, is the probable source of arroba, since the unit was the fourth part of a quintal. Moorish rule in Iberia left the word in Spanish and Portuguese, and Wikipedia repeats a tradition, without a source, that it approximated what a donkey could carry. In Castile the quintal was 100 libras, which makes the arroba 25 libras.

With the Castilian libra of 0.460093 kg set in the standard of 1801, the Spanish arroba comes to about 11.5 kg, the figure used here. Similar values were found in Catalonia, Aragon and Andalusia, while the Portuguese arroba was heavier at about 14.7 kg. The same name also applied to a liquid measure for wine and oil, so the word could mean either a weight or a volume depending on the trade.

Colonial administrations took the unit across the Atlantic, where it hardened into different national values: 15 kg in Brazilian cattle and cotton markets, and 12.5 kg in Colombia, Ecuador and Peru. In Spanish and Portuguese the at sign in email addresses is still called arroba, because the symbol was long used as shorthand for the unit.

Sources: Wikipedia: Arroba; Wikipedia: Spanish customary units

Arroba (Spanish) conversion chart

1 arroba (Spanish) expressed in every other weight & mass unit:

More Spanish & Portuguese units

• libra (Castilian) (weight & mass)
• arroba (Brazilian) (weight & mass)
• vara (Castilian) (length)
• legua (Castilian) (length)

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