m3 to kg – cubic meters to kilograms – mass to volume online

1. Enter volume

Enter a positive number

2. Choose material (or set density)

1 m³ of Water (1000 kg/m³)
=
density ρ = 1000 kg/m³

3. Result in all units — click to copy

Formula

m = V × ρ — mass equals volume times density.
Example: 1 m³ of concrete (ρ = 2400 kg/m³) → m = 1 × 2400 = 2400 kg.

Quick reference: 1 m³ of common materials

Material kg t lb US ton

FAQ

How do I convert m³ to kg?
Multiply the volume in cubic meters by the density of the material in kg/m³. The formula is m = V × ρ. For example, 1 m³ of water (ρ = 1000 kg/m³) weighs 1000 kg, while 1 m³ of concrete (ρ = 2400 kg/m³) weighs 2400 kg.
How do I convert kg to m³?
Divide the mass in kilograms by the density in kg/m³: V = m / ρ. For example, 5000 kg of sand (ρ = 1600 kg/m³) takes up 5000 / 1600 ≈ 3.125 m³. Switch to the kg → m³ tab to do this directly.
Why does the same volume give different weights?
Because materials have different densities. A cubic meter of feathers, water, sand and steel all have very different masses even though the volume is the same. Density (ρ) is the bridge between volume and mass — that is why this calculator asks you to select a material first.
What does 1 m³ of concrete weigh?
Normal-weight concrete is usually taken as 2400 kg/m³ (2.4 t or about 5291 lb per cubic meter). Reinforced concrete is heavier — about 2500 kg/m³ (2.5 t). Lightweight structural concrete ranges from 1600 to 1900 kg/m³.
How do I convert lb/ft³ to kg/m³?
Multiply lb/ft³ by 16.0185 to get kg/m³. So a material listed at 150 lb/ft³ has a density of about 2403 kg/m³. The reverse factor is 1 kg/m³ ≈ 0.06243 lb/ft³.
Can I enter my own density value?
Yes. If your material is not in the list, choose «— custom —» from the dropdown and type the density directly into the «Density (kg/m³)» field. The result updates instantly.
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Cubic meters to kilograms — and back — for any material

This bidirectional converter handles both directions in one place: enter a volume in m³, L, mL, ft³, gal or in³ to get the mass in kg, g, t, lb, oz or short/long tons — or switch the tab to go from a known mass back to the volume it occupies. The math is simple, m = V × ρ for one direction and V = m / ρ for the other, but the result depends entirely on the density (ρ) of the substance, which is why this tool ships with a database of more than 40 common materials.

Pick a material from the dropdown — water, concrete (normal, reinforced, lightweight), cement, mortar, brick, sand (dry/wet), gravel, crushed stone, topsoil, clay, steel, aluminum, copper, lead, zinc, brass, bronze, gold, oak, pine, glass, plastics, rubber, asphalt, snow, oil, gasoline, diesel, milk, honey — and the density auto-fills. Need something custom? Pick «— custom —» and type the density manually. The result block shows every common unit at once and copies to clipboard on click.