Self-weight workflow
Convert mass density for steel, concrete, aluminum, and wood, then calculate unit weight for beam self-weight checks.
Enter a value in any field
Material starting points
Confirm the project material specification before relying on a nominal value.
Next step
Multiply unit weight by cross-sectional area to obtain member self-weight per length, then apply it as a distributed load.
Quick reference
These are convenient starting values, not project specifications. Moisture, alloy, mix design, and product standard can change density.
| From | Equivalent |
|---|---|
| Structural steel | 7,850 kg/m³ |
| Normal-weight concrete | 2,400 kg/m³ |
| Aluminum | 2,700 kg/m³ |
| Softwood (typical) | 500 kg/m³ |
| Water | 1,000 kg/m³ |
Engineering context
Mass density in kg/m³ becomes unit weight in kN/m³ when multiplied by standard gravity and divided by 1,000. Structural steel at 7,850 kg/m³ is approximately 76.98 kN/m³.
Multiply unit weight by member area to obtain a line load. For example, kN/m³ × m² gives kN/m. Verify the actual material and section data used for design.
Density is mass per volume. Unit weight is force per volume. The converter keeps those quantities distinct and shows unit weight as a calculated result.
Where this conversion is used
Questions engineers ask
A commonly used nominal value is 7,850 kg/m³, but the applicable product or material specification should govern.
Multiply mass density by gravitational acceleration. At standard gravity, kg/m³ × 9.80665 ÷ 1,000 gives kN/m³.
Multiply material unit weight by cross-sectional area. The resulting force per length can be applied as a distributed load.
Species, grade, and moisture content materially affect wood density, so use project-specific data when available.
Conversion factors follow SI and U.S. customary unit relationships. Rounded reference values are for convenience; the live converter uses higher-precision factors.