Roman Pound (libra) (libra)

Ancient RomanHistorical unit (no longer in standard use)Approximate value

About 328.9 g, divided into 12 unciae. The abbreviation 'lb' for pound comes from libra.

1 Roman pound (libra) = 0.3289 kilograms (approximately).

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

About the Roman pound (libra)

Libra is the Latin word for a balance, and it named both the scales and the standard weight placed on them. It is also known simply as the Roman pound, and the English abbreviation lb is generally traced back to it.

Roman weights counted in twelfths. A libra held 12 unciae, and further fractions such as the scrupulum and the tiny siliqua, about 0.19 g, allowed fine work. The coin called the as shared this scheme: it began as a pound of bronze, then was cut to two ounces after the First Punic War, one ounce during the Second, and half an ounce by the Lex Papiria of 131 BC.

Modern estimates for the libra range from about 322 to 329 g. The figure used here is 328.9 g, about 11.6 oz or 0.725 of an English pound, which is lighter than the avoirdupois pound of 453.6 g. Surviving weights differ among themselves, which is why the exact value stays uncertain.

Sources: Wikipedia: Roman pound; Wikipedia: Roman units of measurement

Roman Pound (libra) conversion chart

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

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