US Standard Volume

These are the most common measurements:

  • Fluid Ounces
  • Cups
  • Pints
  • Quarts
  • Gallons


fluid ounce

Fluid Ounces (fl oz) are small. 

About how much fits in a small medicine cup.


Fluid Ounce!

"Fluid Ounce" is used for volume, "Ounce" is for mass, and they are different.

  • For example: 1 fluid ounce of honey has a mass of about 1.5 ounces!
  • But for water 1 fluid ounce has a mass of about 1 ounce.

If you mean an ounce of fluid say "fluid ounce" ("fl oz")



A small glass holds about 8 fluid ounces, which is also called 1 cup.

cup 2/3

1 cup = 8 fluid ounces

We can measure volume using special Measuring Cups.

Here we have 2/3 cup (two-thirds of a cup) of milk, or about 5 fluid ounces



A pint is equal to 2 cups (example: a large glass of milk!)

1 pint = 2 cups = 16 fluid ounces



When measuring many cups of liquid all put together we might want to use quarts.

A quart (qt) is the same thing as 4 cups or 2 pints. 

1 quart = 2 pints = 4 cups = 32 fluid ounces

gallon jug


If we still need more liquid we can switch to using gallons.

A gallon (gal) is the same as 16 cups or 8 pints or 4 quarts.  It is the largest liquid measurement.

(Note that a quart is a quarter of a gallon!)

1 gallon = 4 quarts = 8 pints = 16 cups

In Summary:

us gallon quart pint cup

1 gallon = 4 quarts = 8 pints = 16 cups = 128 fluid ounces

Other Volume Measurements

Cubic Inch

cubeVolume is length by length by length,

so the Cubic Inch is a cube that is 1 inch on each side.

The Unit is written many ways, such as:

  • in3
  • inch3
  • cu in
  • cu inch
  • cubic inches
  • etc ...

Barrel of Oil

1 oil barrel (bbl) is equal to 42 gallons (or about 160 Liters)


More Examples

A fluid ounce is:

A pint is:

A quart is:

A gallon is:


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