Density of 2 kg in 4 L
The density of 2 kg in 4 L, compared against common substances. Adjust any field below to try your own numbers.
Density
0.5 kg/L
500.0 kg/m³ — equivalent to 0.5 g/cm³
2 kg occupying 4 L has a density of 0.5 kg/L (500.0 kg/m³, equivalent to 0.5 g/cm³).
Mass
2 kg
Volume
4 L
What is a Density Calculator?
A density calculator finds how much mass is packed into a given volume — or, given any two of mass, volume, and density, solves for whichever value is missing. Density is one of the most fundamental material properties in physics, chemistry, and engineering, since it determines whether an object floats or sinks, how materials are identified, and how structural loads are calculated.
Because density is mass divided by volume, it's an "intensive" property — it doesn't depend on how much material you have. A teaspoon of gold and a brick of gold have the same density, even though their masses and volumes are wildly different.
Compare to Common Substances
Your computed density of 500.0 kg/m³ is highlighted below alongside common reference substances, so you can see roughly what material this density corresponds to.
| Substance | Density (kg/m³) |
|---|---|
| Your Result | 500.0 |
| Air | 1.2 |
| Ice | 917 |
| Oil (vegetable) | 920 |
| Wood (oak) (closest match) | 750 |
| Water | 1000 |
| Concrete | 2400 |
| Aluminum | 2700 |
| Glass | 2500 |
| Iron | 7870 |
| Copper | 8960 |
| Lead | 11340 |
| Mercury | 13534 |
| Gold | 19300 |
The Density Formula
Density is simply mass divided by the volume it occupies. Rearranging the same equation solves for mass or volume when density is already known.
The Greek letter ρ (rho) is the standard symbol for density in physics and engineering. Density is commonly reported in kg/m³ or g/cm³ (numerically equal to kg/L) — water's density of almost exactly 1 g/cm³ at 4°C is the reference point that originally defined the kilogram and the liter.
Why Density Determines Floating and Sinking
An object floats in a fluid if its average density is lower than the fluid's density, and sinks if it's higher — this is the basis of Archimedes' principle. Ice floats on water because ice (about 917 kg/m³) is less dense than liquid water (1000 kg/m³), which is actually unusual: most substances are denser as a solid than as a liquid, but water expands as it freezes due to the hydrogen-bonded crystal structure of ice.
Ships made of steel (far denser than water) still float because their overall shape displaces enough water that their average density — hull, cargo, and the air-filled interior combined — is lower than water's, not because steel itself is buoyant.
Density Depends on Temperature and Pressure
Most materials expand slightly as they warm up (thermal expansion), which lowers their density since the same mass now occupies more volume — this is why the reference densities in the table above are only valid at a specific temperature (typically room temperature or a substance's standard reference point). Gases are especially sensitive: air's density changes noticeably with altitude, temperature, and humidity, while liquids and solids change much less across normal everyday temperature ranges.
Example — Your Current Inputs
2 kg occupying 4 L has a density of 0.5 kg/L (500.0 kg/m³, equivalent to 0.5 g/cm³).
Additional Example — Identifying a Metal
A metal sample has a mass of 178.5 g and, when submerged, displaces 20 mL of water (a classic way to measure irregular volume). Its density is 178.5 g ÷ 20 mL = 8.925 g/cm³ — very close to copper's reference density of 8.96 g/cm³, suggesting the sample is likely copper or a copper-heavy alloy like bronze.
About These Parameters
- Mass
- The amount of matter in the object or substance, measured in kilograms. Mass is not the same as weight — mass stays constant regardless of gravity, while weight (a force) changes depending on where the object is measured.
- Volume
- The amount of three-dimensional space the object or substance occupies, in liters. For irregular solids, volume is often measured by water displacement: submerge the object and record how much the water level rises.
- Density
- Mass per unit volume, entered in kg/L (numerically identical to g/cm³). Leave this field blank if density is what you're solving for.
Frequently Asked Questions
What's the difference between density and specific gravity?
Specific gravity (also called relative density) is a substance's density divided by the density of a reference substance — almost always water for liquids and solids. It's a unitless ratio: a specific gravity of 2.7 means the substance is 2.7 times denser than water. Density, by contrast, always carries units (kg/m³, g/cm³, etc.).
How do I measure the volume of an irregularly shaped object?
Water displacement is the classic method: submerge the object fully in a container of water and measure how much the water level rises — that increase in volume equals the object's volume, regardless of its shape. This only works for objects that don't absorb water and are denser than water (so they sink fully rather than floating).
Why is gold used to check for counterfeits by weighing?
Gold's density (19,300 kg/m³) is unusually high — far higher than common cheaper metals used to fake it, like lead (11,340 kg/m³) or tungsten (19,300 kg/m³, coincidentally very close, which is why tungsten-filled fake gold bars are a real counterfeiting concern). Measuring both mass and volume (often via water displacement) and computing density is a standard, reliable way to verify a gold item is genuine.
Does density change with the amount of substance?
No — density is an intensive property, meaning it doesn't depend on the sample size. A single gram and a full kilogram of the same pure substance, at the same temperature and pressure, have identical density. Mass and volume individually are "extensive" properties that do scale with sample size, but their ratio (density) does not.