Roman Ounces to Grams (uncia to g)

1 Roman ounce (uncia) equals 27.4 grams exactly.

1 Roman ounce (uncia) = 27.4 grams

How to convert Roman ounces to grams

To convert Roman ounces to grams, multiply the number of Roman ounces by 27.4. This factor is exact. To go the other way, multiply grams by 0.03649635036 (rounded).

grams = Roman ounces × 27.4

Example: 10 Roman ounces = 274 grams.

Approximate value. Standards for the Roman ounce (uncia) 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 Ounce (uncia) (uncia)

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

One twelfth of a Roman pound, about 27.4 g. The origin of the word 'ounce'.

Literally meaning a twelfth, uncia was the Roman name for one part in twelve, applied to weight, length and more. As a weight it was a twelfth of a libra. The same word, used for a twelfth of a foot, produced the English inch, so inch and ounce are cousins that split from a single Latin source.

With the libra put at 328.9 g, the uncia comes to about 27.4 g, which is the figure used here. That is a little under the modern avoirdupois ounce of 28.35 g and well below the troy ounce of about 31.1 g. Because the libra itself is estimated anywhere from 322 to 329 g, an uncia could be anywhere from about 26.8 to 27.4 g.

The unit outlived Rome. It continued as the Byzantine ounce, known in Greek as oungia, and in time spread into medieval trade systems across Europe. Many regional ounces developed, such as the Tower ounce and the Dutch ons, which was fixed at 100 g in 1820.

1 Roman ounce (uncia) = 0.0274 kilograms (approximately).

Sources: Wikipedia: Uncia (unit); Wikipedia: Ounce; Wikipedia: Roman pound

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

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