Ounces to Libras (Castilian) (oz to libra)

1 ounce equals 0.06161694076 libras (Castilian) (rounded).

1 ounce = 0.06161694076 libras (Castilian)

How to convert ounces to libras (Castilian)

To convert ounces to libras (Castilian), multiply the number of ounces by 0.06161694076. The factor is rounded to 10 significant digits. To go the other way, multiply libras (Castilian) by 16.22930298 (rounded).

libras (Castilian) = ounces × 0.06161694076

Example: 10 ounces = 0.6161694076 libras (Castilian).

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 these units

Ounce (oz)

US & ImperialCurrent unit

One sixteenth of a pound, exactly 28.349523125 g. Used for food, mail and consumer goods in the US and UK.

A twelfth part is what ounce originally meant. It comes from the Roman uncia, one twelfth of the Roman pound, a word that also gave English the inch. The abbreviation oz does not come from English at all but from the Italian onza or oncia. Over the centuries many regions and trades used different ounces: the English Tower ounce of 29.16 g was abolished by Henry VIII in 1527, and the Dutch ons was redefined as exactly 100 g in 1820.

The avoirdupois ounce used for everyday goods is one sixteenth of a pound, exactly 28.349523125 g or 437.5 grains, the standard in the US and under the UK imperial system. It is not the same as the troy ounce for precious metals, and neither is the fluid ounce, which measures volume. Ounces still describe portions such as steaks and burgers, and they show up in unexpected places: fabric is graded by weight per area, so a 16 oz denim is a heavy cloth, and the copper on a circuit board is specified in ounces, where 1 oz is roughly 34.7 micrometres thick.

1 ounce = 0.02834952313 kilograms (approximately).

Sources: Wikipedia: Ounce; NIST Guide to the SI, Appendix B.8 (mass conversions)

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.

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.

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

Sources: Wikipedia: Spanish customary units; Wikipedia: Arroba

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