US Cups to US Fluid Drams (cup to fl dr)
1 US cup equals 64 US fluid drams exactly.
How to convert US cups to US fluid drams
To convert US cups to US fluid drams, multiply the number of US cups by 64. This factor is exact. To go the other way, multiply US fluid drams by 0.015625.
US fluid drams = US cups × 64
Example: 10 US cups = 640 US fluid drams.
Pints, quarts, gallons and fluid ounces differ between the US and the UK. Units are labeled 'US' or 'imperial' to avoid confusion.
About these units
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
US Fluid Dram (fl dr)
One eighth of a US fluid ounce (3.6967 mL). Used in old pharmacy measures.
Drachma, the Greek coin and weight, lies behind the dram. The Attic drachma weighed about 4.37 g and the Roman one about 3.41 g, and the apothecaries borrowed the name for both a weight and a liquid measure. The US fluid dram is one eighth of a US fluid ounce, 3.6966911953125 mL, and it divides into 60 minims. Its British imperial counterpart, spelled drachm in pharmacy usage from around 1900, is smaller at 3.5516 mL.
Doctors once used the dram as the size of a teaspoonful, and early nineteenth-century prescriptions assumed a teaspoon held 60 minims. By 1876 household teaspoons had grown to 80 to 85 minims, which made that shortcut unreliable for medicine. Pharmacy is now metric, but the fluid dram survives in the capacity of pill bottles and vials. In casual speech a dram of whisky is a small pour, about 25 mL in an English pub and 35 mL in Scotland, which is a different thing from the pharmacist's unit.
1 US fluid dram = 0.003696691195 liters (approximately).
Sources: Wikipedia: Fluid dram; Wikipedia: Minim (unit)
Related conversions
- US fluid drams to US cups (reverse)
- US cups to liters
- US cups to milliliters
- US cups to US gallons
- US cups to US fluid ounces
- US cups to cubic meters
- US cups to cubic centimeters
- US cups to US quarts
- US cups to US pints
- US cups to US tablespoons
- US cups to US teaspoons
- US cups to metric cups
- US cups to metric tablespoons
- Liters to US fluid drams
- Milliliters to US fluid drams
- US gallons to US fluid drams
- US fluid ounces to US fluid drams
See all volume units.