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.

1 US fluid ounce = 0.02957352956 liters (approximately).

1 US fluid ounce = 0.02957352956 liters

About the US 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.

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

US Fluid Ounce conversion chart

1 US fluid ounce expressed in every other volume unit:

Unit1 US fluid ounce
Liters0.02957352956
Milliliters29.57352956
US Gallons0.0078125
US Cups0.125
Cubic Meters0.00002957352956
Cubic Centimeters29.57352956
US Quarts0.03125
US Pints0.0625
US Tablespoons2
US Teaspoons6
Metric Cups0.1182941183
Metric Tablespoons1.971568638
Metric Teaspoons5.914705913
Imperial Gallons0.006505267067
Imperial Pints0.05204213654
Imperial Fluid Ounces1.040842731
Cubic Inches1.8046875
Cubic Feet0.00104437934
Cubic Yards0.00003868071631
Oil Barrels0.0001860119048
Cubic Millimeters29,573.52956
Microliters29,573.52956
Centiliters2.957352956
Deciliters0.2957352956
Hectoliters0.0002957352956
Cubic Kilometers2.957352956×10⁻¹⁴
Australian Tablespoons1.478676478
US Legal Cups0.1232230398
Imperial Quarts0.02602106827
Cubic Miles7.095067058×10⁻¹⁵
Wine Bottles0.03943137275
Magnums0.01971568638
Jeroboams0.009857843188
Methuselahs0.004928921594
Nebuchadnezzars0.001971568638
US Gills0.25
US Fluid Drams8
US Minims480
Jiggers0.6666666667
Pinches96
Dashes48
Imperial Gills0.2081685462
US Bushels0.0008392255931
US Pecks0.003356902373
US Dry Quarts0.02685521898
US Dry Pints0.05371043796
US Dry Barrels0.000255766369
US Liquid Barrels0.000248015873
UK Beer Barrels0.000180701863
Firkins0.0007228074519
Kilderkins0.000361403726
Hogsheads (ale)0.0001204679087
Tierces0.0001860119048
Hogsheads (wine)0.0001240079365
Puncheons0.00009300595238
Butts (pipe)0.00006200396825
Tuns0.00003100198413
Acre-feet2.39756506×10⁻⁸
Cords0.000008159213596
Board Feet0.01253255208
Cyathi0.6501661461
Sextarii0.05418051218
Congii0.009030085363
Modii0.003386282011
Amphorae0.00112876067
Omers0.01344251344
Hin0.008065508063
Baths (biblical)0.001344251344
Homers0.0001344251344
Gō0.163941557
Shō0.0163941557
Tō0.00163941557
Koku0.000163941557
Charkas0.2404467333
Shtofs0.02404467333
Vedros0.002404467333

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