Libra (Castilian) (libra)

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

About 460.09 g, the Castilian pound. The Spanish libra and arroba were used throughout Spain and its colonies.

1 libra (Castilian) = 0.460093 kilograms (approximately).

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

About the libra (Castilian)

Latin libra, a pound, gave Castilian Spanish its basic weight, subdivided into 16 onzas of about 28 g each. Castile kept the unit through the Middle Ages, and the national standard enacted in 1801 fixed it at exactly 0.460093 kg, the figure used here. That is about 460 g, a little more than a half-ounce above the avoirdupois pound.

Before and after that decree, local libras differed a great deal. Huesca used one near 0.351 kg, Pontevedra one near 0.579 kg, and apothecaries in Barcelona used a medicinal libra of only 0.300 kg. Standardization on paper did not remove these customs quickly, so merchants had to know which city's pound a price referred to.

Larger Castilian weights were built from the libra. The arroba was 25 libras, about 11.5 kg, and the quintal 100 libras, about 46 kg. These were used for wool, olive oil, tobacco, silver and other goods across Spain and its American colonies until metric weights replaced them in the nineteenth century, though the libra survives informally as the pound in Latin America.

Sources: Wikipedia: Spanish customary units; Wikipedia: Arroba

Libra (Castilian) conversion chart

1 libra (Castilian) expressed in every other weight & mass unit:

More Spanish & Portuguese units

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

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