Pounds to Roman Pounds (lb to libra)
1 pound equals 1.379119398 Roman pounds (rounded).
How to convert pounds to Roman pounds
To convert pounds to Roman pounds, multiply the number of pounds by 1.379119398. The factor is rounded to 10 significant digits. To go the other way, multiply Roman pounds by 0.7251003803 (rounded).
Roman pounds = pounds × 1.379119398
Example: 10 pounds = 13.79119398 Roman pounds.
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
Pound (lb)
Exactly 0.45359237 kg, divided into 16 ounces. The standard unit of weight in the US and common in the UK.
Why is pound abbreviated lb? The answer is Roman. The English word comes from the Latin libra pondo, roughly the weight measured in libra, and the symbol keeps the first word. The Roman libra was divided into 12 unciae. The avoirdupois pound of 16 ounces came into general use around 1300 and was initially equal to 6,992 troy grains; under Elizabeth I it was redefined as 7,000 grains. The UK's Weights and Measures Act 1878 set the imperial standard pound as a platinum cylinder, and the troy pound was abolished for trade the following year.
Today the pound is defined from the kilogram. The International Yard and Pound Agreement of 1959 fixed it at exactly 0.45359237 kg, and the UK's Weights and Measures Act 1963 wrote the same figure into law. Pounds remain the everyday unit for body weight, groceries and shipping in the United States and are widely used in the UK. The word also survives in odd places: a six-pounder cannon was named for the weight of its shot, not its own.
1 pound = 0.45359237 kilograms (exactly).
Sources: Wikipedia: Pound (mass); NIST Guide to the SI, Appendix B.8 (mass conversions)
Roman Pound (libra) (libra)
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
Related conversions
- Roman pounds to pounds (reverse)
- Pounds to kilograms
- Pounds to grams
- Pounds to metric tons
- Pounds to ounces
- Pounds to milligrams
- Pounds to micrograms
- Pounds to carats
- Pounds to stone
- Pounds to short tons
- Pounds to long tons
- Pounds to troy ounces
- Pounds to daltons
- Kilograms to Roman pounds
- Grams to Roman pounds
- Metric tons to Roman pounds
- Ounces to Roman pounds
See all weight & mass units.