How many kilograms are in 4 liters of water?

"Liters to Kilograms" Calculator

How many kilograms are in 4 liters of water?

Answer

4 liters of water weighs

3.99 kg

The density of water is 0.998 kg/L (liquid water at 20 °C; rounding to 1.00 kg/L is fine for everyday use).

How the mass of 4 liters of water was worked out

mass = volume × density

0.998 kg/L × 4 L

≈

3.99 kg

The density comes from FAO/INFOODS Density Database v2.0. Liquid water at 20 °C; rounding to 1.00 kg/L is fine for everyday use.

Why a liter and a kilogram are not the same thing

A liter measures volume, a kilogram measures mass, and density is what ties them together: how many kilograms one liter of this particular substance comes to. The coincidence that makes people treat them as one thing is historical — in 1795 the gram was defined as the mass of one cubic centimeter of water, so a liter of water weighed a kilogram by construction. For anything else the equality breaks.

The extremes of this page make it obvious: one liter of LPG weighs 0.51 kg, while one liter of densely packed sand weighs 2 kg — four times more at the very same volume.

If the substance is not known in advance, start from how many kilograms are in 4 liters — the same volume across every substance at once.

The other way round: how much room a kilogram takes

This page starts from a volume and answers in kilograms. The opposite question — how many liters a given mass comes to — is what the kilograms to liters calculator is for. Both read the same density table, so the two pages agree wherever the answer is volume times density.

For water that means 4 liters weighs 3.99 kg here, and one kilogram of it takes 1 liter there.

Related Calculations

About "Liters to Kilograms" Calculator

This calculator converts liters to kilograms through the density of the substance: mass equals volume times density. A liter on its own has no weight — a liter of water weighs almost exactly a kilogram, a liter of honey close to one and a half, and a liter of gasoline about three quarters. For example, it can help you find out how many kilograms are in 4 liters of water? (The answer is: 3.99). For bulk materials — cement, sand, soil, coal, vegetables — density depends on how the material is packed, so the page prints a range and names the state it was measured in, instead of passing one number off as a physical constant.

"Liters to Kilograms" Calculator

How much 4 liters of each substance weighs

Substance	Mass	Density, kg/L
Beer	4.04 kg	1.01
Cement	5–5.6 kg	1.25–1.4
Coal	2.62–5.06 kg	0.654–1.266
Cucumbers	2.48–2.56 kg	0.62–0.64
Diesel	3.34 kg	0.834
Gasoline	2.96 kg	0.74
Honey	5.68 kg	1.42
Juice	4.24 kg	1.06
LPG	2.04 kg	0.51
Milk	4.12 kg	1.03
Mineral spirits	3.12 kg	0.78
Motor oil	3.4 kg	0.85
Sand	6.6–8 kg	1.65–2
Soil	5.2–6 kg	1.3–1.5
Sugar	2.88–3.6 kg	0.72–0.9
Tomatoes	2.2–2.4 kg	0.55–0.6
Vegetable oil	3.68 kg	0.92
Wall primer	4 kg	1
Water	3.99 kg	0.998

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