Cyathi to US Cups (cyathus to cup)
1 cyathus equals 0.1922585492 US cups (rounded).
How to convert cyathi to US cups
To convert cyathi to US cups, multiply the number of cyathi by 0.1922585492. The factor is rounded to 10 significant digits. To go the other way, multiply US cups by 5.201329169 (rounded).
US cups = cyathi × 0.1922585492
Example: 10 cyathi = 1.922585492 US cups.
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
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
US Cup (cup)
One sixteenth of a US gallon, 236.588 mL (8 US fluid ounces). The standard US recipe cup.
Cups began as household drinking vessels, not scientific units, which is why they remain the messiest measures in the kitchen. The US customary cup was defined by slicing up the gallon: half a pint, or eight US fluid ounces, about 236.6 milliliters. Unlike the larger units, nobody ever fixed it to a physical vessel, so it exists only as a fraction of the gallon.
The customary cup is not the only American cup. For nutrition labels, US regulation defines a cup as exactly 240 milliliters, a rounder figure that sits slightly above the customary size. Packaged foods therefore list a serving in the legal cup while a measuring cup from the hardware store follows the customary definition. The gap is 3.4 milliliters, which hardly matters for soup but can matter in baking. Cup measures also hide the weight of dry ingredients, since a cup of sifted flour and a cup of packed flour differ substantially, which is why much of the world prefers grams.
1 US cup = 0.2365882365 liters (exactly).
Sources: Wikipedia: Cup (unit); NIST SP 811, Appendix B.8: conversion factors for volume; 21 CFR 101.9: nutrition labeling household measures
Related conversions
- US cups to cyathi (reverse)
- Cyathi to liters
- Cyathi to milliliters
- Cyathi to US gallons
- Cyathi to US fluid ounces
- Liters to US cups
- Milliliters to US cups
- US gallons to US cups
- US fluid ounces to US cups
- Cubic meters to US cups
- Cubic centimeters to US cups
- US quarts to US cups
- US pints to US cups
- US tablespoons to US cups
- US teaspoons to US cups
- Metric cups to US cups
- Metric tablespoons to US cups
See all volume units.