What is the Volume Conversion Calculator?
This tool converts a volume from one unit to another across the most common liquid measures: liters (L), milliliters (mL), and US customary units — gallons, quarts, pints, cups, and fluid ounces. Note that the gallon, quart, pint, cup and fluid ounce here use US customary definitions, which differ from UK (imperial) values; for example, a US gallon is 3.785 L while a UK gallon is 4.546 L.
How to use it
Enter the numeric value you want to convert, pick the unit you are converting from, then pick the unit you want the answer in. The calculator shows the converted amount plus the equivalent in liters so you can sanity-check the result.
The formula explained
Every unit is defined by how many liters it equals (its factor). The conversion is a two-step process: first turn the input into liters by multiplying by the source factor, then turn liters into the target unit by dividing by the target factor. In one line:
$$\text{result} = \dfrac{\text{value} \times f_{\text{from}}}{f_{\text{to}}}$$The key factors are \(1\ \text{gal} = 3.785411784\ \text{L}\), \(1\ \text{qt} = 0.946352946\ \text{L}\), \(1\ \text{pt} = 0.473176473\ \text{L}\), \(1\ \text{cup} = 0.2365882365\ \text{L}\), and \(1\ \text{fl oz} = 0.0295735296\ \text{L}\).
Worked example
Convert 2 US gallons to liters:
$$2 \times 3.785411784 = 7.570823568\ \text{L}$$To then express that in cups, divide by \(0.2365882365\):
$$7.570823568 \div 0.2365882365 \approx 32\ \text{cups}$$which matches the fact that there are 16 cups per gallon.
FAQ
Are these US or UK units? The gallon, quart, pint, cup, and fluid ounce use US customary values. Liters and milliliters are metric and identical worldwide.
How many milliliters are in a US cup? A US cup is \(0.2365882365\ \text{L}\), which is about \(236.59\ \text{mL}\).
Why is my answer slightly different from a quick mental estimate? The calculator uses exact conversion factors, so it can differ from rounded shortcuts like "1 gallon ≈ 3.8 L."
