Density Calculator
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| Common Material | Approx. Density (kg/m³) |
|---|---|
| Air (at sea level) | 1.2 |
| Water (fresh, 4°C) | 1,000 |
| Seawater | 1,025 |
| Aluminum | 2,700 |
| Concrete | 2,400 |
| Steel | 7,850 |
| Gold | 19,300 |
The Density Formula
Density is defined as mass per unit volume: ρ = m / V, where ρ (rho) is density, m is mass, and V is volume. This calculator rearranges the same formula to solve for whichever quantity you're missing — mass = ρ × V, or volume = m / ρ — after converting your inputs to a consistent metric base (kilograms and cubic meters) internally, then converting the result back to your chosen output unit. This is the standard approach used in physics and engineering for any homogeneous material or fluid.
A Common Mix-Up: Density vs. Specific Gravity
Density and specific gravity are often confused because they're numerically close for water-based substances. Specific gravity is a unitless ratio of a substance's density to the density of water (about 1,000 kg/m³ at 4°C), while density itself always carries units. A specific gravity of 2.7 (aluminum) simply means "2.7 times denser than water" — multiply by water's density in your unit of choice to get the actual density figure.
Practical Uses
Density calculations show up constantly in shipping (dimensional weight), material selection, and quality control — checking whether a poured batch of concrete or a liquid sample matches its expected composition. If you're working with a physical volume you need to measure first, from a room to a container, the square footage calculator can help with the area side of that math before you convert to a full volume.
Frequently Asked Questions
How do I calculate density if I know mass and volume?
Divide mass by volume: density = mass / volume. For example, an object with a mass of 5 kg and a volume of 0.005 cubic meters has a density of 1,000 kg/m3. Select "Density" in the solve-for menu, enter the mass and volume with their units, and the calculator converts everything to a consistent base before computing the result.
What's the difference between density and specific gravity?
Density is mass per unit volume and always has units (like kg/m3 or g/cm3). Specific gravity is a unitless ratio comparing a substance's density to the density of water (about 1,000 kg/m3 at 4°C). A specific gravity of 2.7 means the material is 2.7 times as dense as water; multiply by water's density in your chosen unit to convert specific gravity into an actual density figure.