Roman Pounds to Grams (libra to g)

1 Roman pound (libra) equals 328.9 grams exactly.

1 Roman pound (libra) = 328.9 grams

How to convert Roman pounds to grams

To convert Roman pounds to grams, multiply the number of Roman pounds by 328.9. This factor is exact. To go the other way, multiply grams by 0.003040437823 (rounded).

grams = Roman pounds × 328.9

Example: 10 Roman pounds = 3,289 grams.

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 these units

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.

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.

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

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

Gram (g)

Metric (SI)Current unit

One thousandth of a kilogram. The standard unit for food quantities and small objects.

A gram was once defined as a small drop of the natural world. The French National Convention of 1795 set it as the absolute weight of a volume of pure water equal to a cube one hundredth of a metre on each side, a cubic centimetre. The reference temperature was first the melting point of ice and was later changed to the temperature of maximum density of water, about 4 degrees Celsius. The word came into French as gramme, from Late Latin gramma, itself from the Greek for a letter or small mark; in Late Antiquity it meant about one twenty-fourth of an ounce.

The gram was the base unit of mass in the centimetre-gram-second system, but in 1960 the SI took the kilogram as its base unit, which made the gram one thousandth of it. That is why it appears in so many everyday places: it is the standard for non-liquid ingredients in cooking and shopping, and nutrition labels commonly list contents per 100 g. For a sense of scale, a small paper clip or a pen cap weighs about a gram, and a Japanese 1-yen coin is close to exactly that, while a US penny is around 2.5 g.

1 gram = 0.001 kilograms (exactly).

Sources: Wikipedia: Gram; Wikipedia: Kilogram

Related conversions

See all weight & mass units.