US Fluid Ounces to Firkins (fl oz to firkin)

1 US fluid ounce equals 0.0007228074519 firkins (rounded).

1 US fluid ounce = 0.0007228074519 firkins

How to convert US fluid ounces to firkins

To convert US fluid ounces to firkins, multiply the number of US fluid ounces by 0.0007228074519. The factor is rounded to 10 significant digits. To go the other way, multiply firkins by 1,383.494314 (rounded).

firkins = US fluid ounces × 0.0007228074519

Example: 10 US fluid ounces = 0.007228074519 firkins.

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 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

Firkin (firkin)

Imperial (British)Traditional unit (still used in some regions)

9 imperial gallons (40.9 L), a quarter of a barrel. A traditional cask size for beer.

Probably from Middle English ferdekyn, which in turn likely comes from a Middle Dutch diminutive of vierde, fourth, the firkin is literally a little quarter: a quarter of a barrel. For beer in Britain that means 9 imperial gallons, about 41 liters (40.9 L here), or 72 imperial pints.

The word has been used for other goods too. A wine firkin was much bigger, at 70 imperial gallons by one reckoning, while British butter and cheese were sold by the firkin of 56 pounds, about 25 kilograms. An American dry firkin of 9 US gallons is only about 34 liters, and the word could also mean any small wooden tub for butter, lard or fish. Authors such as William Robinson in 1825 treated it as a recognised trade measure.

1 firkin = 40.91481 liters (exactly).

Sources: Wikipedia: Firkin (unit); Wikipedia: Barrel (unit); Wikipedia: Cask ale

Related conversions

See all volume units.