Pounds to Liters

A pound does not become liters on its own

A pound measures weight, a liter measures volume, and density is what converts one into the other. The lighter the substance, the more liters the same pounds fill: five pounds of water is 2.27 liters, five pounds of vegetable oil 2.47 liters, and five pounds of liquid propane 4.47 liters. When no substance is named, this calculator answers for water and shows the rest in a table.

The international avoirdupois pound is exactly 0.45359237 kilograms, so the first step turns the weight into kilograms; density in kilograms per liter then turns kilograms into liters. No other constant is involved — the liter is the volume unit of the density itself.

Three steps

1. Turn the pounds into kilograms — multiply by 0.45359237: ten pounds are 4.5359237 kg exactly.
2. Find the density of the substance — in the table below; water at 20 °C is 0.998 kg/L.
3. Divide the kilograms by the density: ten pounds of water is 4.55 liters — division rarely comes out even, so the figure is rounded.

How many liters one pound and five pounds fill

If the substance is not known in advance, start from how many liters 5 lbs is — water first, then the other liquids at the same weight. The opposite question, what a number of liters weighs, is on the liters to pounds page.

Where this actually comes up

• Containers. A recipe or a supplier gives a weight, the container is marked in liters: 35 lbs of vegetable oil is 17.3 liters, so it will not fit a 15-liter jug.
• Propane. A 20-lb grill cylinder holds 17.9 liters of liquid propane — the figure to compare with a tank whose volume is printed in liters.
• Water. A payload of 100 lbs of water is 45.5 liters; a 40-lb limit on a hiking or camping load is 18.2 liters.
• Milk and dairy. Ten pounds of milk is 4.4 liters — milk is a little denser than water, so it takes a little less room.
• Imported goods. US labels state net weight in pounds, European tanks and bottles are sized in liters; converting one into the other is how you know whether it fits.

Where the pound and the liter come from

The pound used here is the international avoirdupois pound, fixed in 1959 at exactly 0.45359237 kilograms by agreement between the United States and the Commonwealth. The liter was introduced with the metric system in 1795 as the volume of a cube one tenth of a meter on each side; between 1901 and 1964 it was defined as the volume of one kilogram of water, and in 1964 it went back to exactly one cubic decimeter.

Pounds to liters or kilograms to liters

The kilograms to liters page answers the same question starting from kilograms, with the same density table; every result page here names the kilograms too. For US gallons instead of liters, use pounds to gallons.

Doing it in your head

For water, halve the pounds and take off a tenth: a liter of water weighs 2.2 lbs, a little over two pounds, so 40 lbs is a bit less than 20 liters — the full calculation gives 18.2 liters. Milk gives almost the same figure (2.27 lbs a liter), vegetable oil about a tenth more liters (2.03 lbs a liter), liquid propane almost twice as many (1.12 lbs a liter).

Where the densities come from

The densities are shared with the kilograms to liters and liters to kilograms pages, and every figure carries a citable source: the FAO/INFOODS density database for water, milk and vegetable oil, ISO 3993 for propane. Water is taken at 20 °C (68 °F).