Liters to Pounds

A liter does not become pounds on its own

A liter measures volume, a pound measures weight, and density is what converts one into the other. A liter of water weighs 2.2 lbs, a liter of gasoline 1.63 lbs and a liter of liquid propane only 1.12 lbs — the same liter, three different weights. When no substance is named, this calculator answers for water and shows the rest in a table.

Density in kilograms per liter already gives the weight of one liter in kilograms; the only conversion left is from kilograms to pounds. The international avoirdupois pound is exactly 0.45359237 kilograms, so dividing by it is the same as multiplying by about 2.2046.

Three steps

1. Find the density of the substance — in the table below, in kilograms per liter (the same number as grams per milliliter).
2. Multiply the liters by it to get kilograms: twenty liters of water at 0.998 kg/L are 20 × 0.998 = 19.96 kg.
3. Divide by 0.45359237 to get pounds: 44 lbs. The figure is rounded, so multiplying rounded numbers can differ in the last digit.

What one liter and five liters weigh

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

Where this actually comes up

• Water jugs and bottles. A 20-liter water jug holds 44 lbs of water; a 1.5-liter bottle 3.3 lbs.
• Drums and barrels. A 200-liter drum of water weighs 440 lbs — more than most hand trucks are rated for.
• Fuel. A 50-liter car tank full of gasoline adds 81.6 lbs; cars sold outside the US state their tank size in liters, and payload in the US is counted in pounds.
• Aquariums. A 100-liter tank carries 220 lbs of water before the glass, gravel and stand — the number to check against a floor or a shelf.
• Travel and hiking. Two liters of water in a pack weigh 4.4 lbs, which is why water is the heaviest thing most hikers carry.

Where the liter and the pound come from

The liter was introduced with the metric system in 1795 as the volume of a cube one tenth of a meter on each side. From 1901 to 1964 it was defined instead as the volume of one kilogram of water, which made it very slightly larger; in 1964 it went back to exactly one cubic decimeter. That history is why a liter of water weighs almost exactly a kilogram. The pound was tied to the metric system in 1959, when the United States and the Commonwealth agreed on the international pound of exactly 0.45359237 kilograms.

Liters to pounds or liters to kilograms

Only the unit of weight differs. The liters to kilograms page answers the same question in kilograms from the same density table, and every result page here names the kilograms too. For US gallons instead of liters, use gallons to pounds.

Doing it in your head

For water, multiply the liters by 2.2: a liter of water is almost exactly a kilogram, and a kilogram is about 2.2046 pounds — so a 200-liter drum of water is about 440 lbs, while the full calculation gives 440 lbs. Gasoline weighs about three quarters of water (1.63 lbs a liter), liquid propane about half (1.12 lbs).

Where the densities come from

Every figure carries a citable source: the FAO/INFOODS density database for water, fuel standards for gasoline, ISO 3993 for propane. Water is taken at 20 °C (68 °F), where its density is 0.998 kg/L; colder water is a touch denser, a difference no household scale can see.