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" 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")


cup 2/3


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

1 cup = 8 fluid ounces

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


By the way ... we can measure volume using special Measuring Cups ... !



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


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!)

gallon juh


In Summary:

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

us gallon quart pint cup

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:

  • very close to 30 milliliters (metric volume)
  • more precisely 29.5735297 milliliters

A pint is:

  • about half a liter
  • more precisely 473.176473 milliliters

A quart is:

  • about a liter
  • more precisely 946.352946 milliliters