Modii to US Fluid Ounces (modius to fl oz)

1 modius equals 295.3091316 US fluid ounces (rounded).

1 modius = 295.3091316 US fluid ounces

How to convert modii to US fluid ounces

To convert modii to US fluid ounces, multiply the number of modii by 295.3091316. The factor is rounded to 10 significant digits. To go the other way, multiply US fluid ounces by 0.003386282011 (rounded).

US fluid ounces = modii × 295.3091316

Example: 10 modii = 2,953.091316 US fluid ounces.

Pints, quarts, gallons and fluid ounces differ between the US and the UK. Units are labeled 'US' or 'imperial' to avoid confusion.

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

About these units

Modius (modius)

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

Sixteen sextarii, about 8.73 L. The standard Roman dry measure, used for grain.

Grain, not wine, was what the modius measured. It belonged to the Roman dry scale, where it stood at the top of the ordinary series, with the semimodius at half its size and the larger modius castrensis, about 12.93 L, above it. Wikipedia's table gives the plain modius as 8.73 L, the figure used here, and describes it as 2 and two thirds congii or 16 sextarii.

That puts it at one third of an amphora quadrantal, so liquid and dry measures shared a single system built on the cubic Roman foot. Because it is a multiple of the sextarius, the usual uncertainty applies: surviving vessels suggest the sextarius ranged from 500 to 580 mL, which would put the modius between roughly 8.0 and 9.3 L. A bronze modius stamped with a reference to imperial regulation of weights and measures survives, which shows that the state tried to keep the size fixed. Today it is a little under a quarter of a US bushel.

1 modius = 8.733333333 liters (approximately).

Sources: Wikipedia: Ancient Roman units of measurement

US Fluid Ounce (fl oz)

US customaryCurrent unit

One 128th of a US gallon, 29.5735 mL. Not the same as the weight ounce, and about 4% larger than the imperial fluid ounce.

Fluid ounce began as an attempt to link volume to weight: the volume occupied by one ounce of some substance, such as wine in England or water in Scotland. Definitions varied by region and by liquid. When Britain defined its imperial gallon in 1824 as the space of ten pounds of water, the imperial fluid ounce came out so that an ounce of water weighs about one avoirdupois ounce. The US fluid ounce followed a different path and comes from the older wine gallon.

The US fluid ounce is exactly 1/128 of a US gallon, 29.5735295625 milliliters, about 4 percent bigger than the imperial one at 28.4130625 milliliters. American nutrition labels use yet another figure, treating one fluid ounce as 30 milliliters, a convenient rounding for serving sizes. The name is a trap, because a fluid ounce measures space while a weight ounce measures mass. A US fluid ounce of water weighs a bit more than an ounce of weight, while a fluid ounce of honey weighs considerably more.

1 US fluid ounce = 0.02957352956 liters (approximately).

Sources: Wikipedia: Fluid ounce; NIST SP 811, Appendix B.8: conversion factors for volume; 21 CFR 101.9: nutrition labeling household measures

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