Density (ρ) is mass per unit volume, typically in kg/m³ or g/cm³. It describes how tightly matter is packed. Steel ≈ 7850 kg/m³, aluminum ≈ 2700 kg/m³, water = 1000 kg/m³.

How do I calculate mass from density and volume?

Mass = Density × Volume (m = ρ × V). For example: a 0.5 m³ block of steel (7850 kg/m³) weighs 7850 × 0.5 = 3925 kg.

How do I calculate volume from dimensions?

Cube: V=a³. Cylinder: V=π×r²×h. Sphere: V=4/3×π×r³. Hollow cylinder: V=π×(R²-r²)×h. Cone: V=1/3×π×r²×h.

Buoyancy force equals the weight of displaced fluid: F_b = ρ_fluid × V × g. An object floats if its density is less than the fluid density. Steel sinks in water (7850 > 1000 kg/m³).

What is specific gravity?

Specific gravity (SG) is the ratio of a material's density to water density (1000 kg/m³). It is dimensionless. Steel SG ≈ 7.85, aluminum SG ≈ 2.70, titanium SG ≈ 4.51.

Free Engineering Tool

Density / Mass / Volume Calculator

Solve for any one of density, mass, or volume. 30+ material presets, shape-based volume calculator, buoyancy check, and multi-unit output.

ρ = m / V 30+ Materials Shape Volume Buoyancy

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Density ρ (kg/m³)

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Mass (kg)

Volume (m³)

Length / Side a (mm)

Width b (mm)

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Outer Radius R (mm)

Inner Radius r (mm, hollow only)

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Results

Density ρ

—

Mass m

—

Volume V

—

Weight (multiple units)

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Specific Gravity

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Buoyancy in Water

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Fundamental Formulas

Shape Volume Formulas

Buoyancy

An object floats if ρ_object < ρ_fluid. The net submerged weight = m×g − ρ_fluid×V×g.

Practical Example

Example — Steel hollow cylinder (pipe)

Given: OD=100mm, ID=80mm, Length=500mm, ρ=7850 kg/m³

V = π×(50²−40²)×500 = π×(2500−1600)×500 = 1,413,717 mm³ = 0.001414 m³

m = 7850 × 0.001414 = 11.1 kg = 24.4 lb

Weight in water: F_b = 1000 × 0.001414 × 9.81 = 13.87 N → submerged weight = 95.0 N

Material Density Database

Material	kg/m³	g/cm³	lb/ft³
Carbon Steel	7,850	7.85	490
Stainless 304	7,930	7.93	495
Stainless 316	8,000	8.00	499
Cast Iron (Gray)	7,200	7.20	449
Aluminum 6061	2,700	2.70	169
Aluminum 7075	2,810	2.81	175
Copper	8,900	8.90	556
Brass	8,500	8.50	531
Bronze	8,800	8.80	549
Titanium	4,510	4.51	282
Magnesium	1,740	1.74	109
Lead	11,340	11.34	708
Nickel	8,908	8.91	556
Gold	19,300	19.30	1,205
HDPE	920	0.92	57
PVC	1,400	1.40	87
PTFE (Teflon)	2,200	2.20	137
Concrete	2,500	2.50	156
Glass	2,200	2.20	137
Oak Wood	600	0.60	37
Water (20°C)	1,000	1.00	62.4
Seawater	1,025	1.025	64.0
Diesel Fuel	870	0.87	54.3

Density Mass Volume Calculator | ρ=m/V | Shape Calculator | Free Tool

Published by Nikolai Shelkovenko on February 15, 2026 February 15, 2026