US Fluid Ounces to Cyathi (fl oz to cyathus)
1 US fluid ounce equals 0.6501661461 cyathi (rounded).
How to convert US fluid ounces to cyathi
To convert US fluid ounces to cyathi, multiply the number of US fluid ounces by 0.6501661461. The factor is rounded to 10 significant digits. To go the other way, multiply cyathi by 1.538068394 (rounded).
cyathi = US fluid ounces × 0.6501661461
Example: 10 US fluid ounces = 6.501661461 cyathi.
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 cyathus varied by place and period, so this converter uses the most commonly cited value. Treat results as estimates, not exact figures.
About these units
US Fluid Ounce (fl oz)
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
Cyathus (cyathus)
One twelfth of a sextarius, about 45 mL. A small Roman ladle or wine cup.
Greek kyathos, a cup or ladle, lies behind the Latin cyathus. In Roman use it was the small dipper for taking wine from a mixing bowl and filling drinking cups, so it served as the basic unit for serving rather than for trade. Wikipedia lists it as 1/72 of a congius, or 45 mL, the figure used here.
It appears in both the liquid and the dry tables, where it is one twelfth of a sextarius, so twelve cyathi filled the sextarius and 576 filled an amphora quadrantal. The unit therefore inherits the uncertainty of the sextarius, which scholars estimate at 500 to 580 mL from surviving vessels, putting a cyathus somewhere between about 42 and 48 mL. In modern terms it is a little over one and a half US fluid ounces, about the size of a shot glass or a generous tablespoon and a half.
1 cyathus = 0.04548611111 liters (approximately).
Sources: Wikipedia: Ancient Roman units of measurement; Wikipedia: Cyathus (genus), on the Greek kyathos
Related conversions
- Cyathi to US fluid ounces (reverse)
- US fluid ounces to liters
- US fluid ounces to milliliters
- US fluid ounces to US gallons
- US fluid ounces to US cups
- US fluid ounces to cubic meters
- US fluid ounces to cubic centimeters
- US fluid ounces to US quarts
- US fluid ounces to US pints
- US fluid ounces to US tablespoons
- US fluid ounces to US teaspoons
- US fluid ounces to metric cups
- US fluid ounces to metric tablespoons
- Liters to cyathi
- Milliliters to cyathi
- US gallons to cyathi
- US cups to cyathi
See all volume units.