Fluid ounce
history
A fluid ounce (abbreviated fl oz, fl. oz. or oz. fl.) is a unit of volume equal to about 29.57 ml, in the US. It is used in both the imperial and the US customary systems, and it is sometimes referred to simply as an ounce in cases where no confusion with the unit of weight (also called an ounce) is likely to occur.
Definitions and equivalences
- Imperial fluid ounce
{|
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|height=120%|1 imperial fluid ounce
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|align=right|imperial gallon
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|align=right | |imperial pint
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|align=right | |imperial gill
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|align=right|8 | imperial fluid drams
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|align=right|28.4130625 | millilitres | cubic inches
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|align=right|1 | avoirdupois ounce of water at [The imperial gallon was originally defined as the volume occupied by ten avoirdupois pounds of water at , weighed in air with brass weights.]
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|align=right|0.960759940 | US fluid ounce
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- US customary fluid ounce
{|
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| 1 US fluid ounce | =
|align=right | |US gallon
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|align=right | |US quart
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|align=right | |US pint
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|align=right | |US cup
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|align=right | |US gill
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|align=right|2 | tablespoons
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|align=right|6 | teaspoons
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|align=right|8 | US fluid drams
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|align=right|1.80468754 | cubic inches[One US gallon is defined as 231 cubic inches.]
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|align=right|29.5735295625 | millilitres (or the same number of cubic centimetres (cm³))
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|align=right|1.040842731 | imperial fluid ounces
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|align=right|1.041 | avoirdupois ounce (29.5 g) of water at
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- US food labeling fluid ounce
US regulation 21 CFR 101.9(b)(5)(viii) also defines a fluid ounce as exactly 30 millilitres, but this is for use in nutrition labeling only. | ≈
|align=right|1.055852392 | imperial fluid ounces | US customary fluid ounces | cubic inches
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- Other useful conversions
Given the definitions above, the number of US fluid ounces in one litre is
: × 1000 = 33.8140
There are thus about 34 customary US fluid ounces in one litre.
Similarly, there are exactly 33 US food-labelling fluid ounces in a litre.
References and notes
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