Specific weight converter
Convert unit weight between kN/m³, N/m³, lbf/ft³, lbf/in³, kgf/m³ and tf/m³.
That's about the same as compacted soil. Under standard gravity that is a density of 1,835 kg/m³.
What it means
How heavy is that material?
Typical values. Soil depends on moisture and compaction; concrete on its aggregate and reinforcement.
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Your specific weight in every unit
Learn
Three things worth knowing
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1 kN/m³ ≈ 6.4 lbf/ft³
So 24 kN/m³ of concrete is about 153 lbf/ft³, and water’s 9.81 kN/m³ is 62.4 lbf/ft³.
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Weight, not mass
Density counts kilograms; specific weight counts newtons. Engineers prefer it because the load on a footing is a force, and it already includes gravity.
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kN/m³ is not g/cm³
Water is 1 g/cm³ but 9.81 kN/m³. Divide by 9.81 to get density in tonnes per cubic meter.
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Background
About specific weight
Specific weight, or unit weight, is how much a cubic meter of material weighs: its density times gravity. Structural and geotechnical engineers work in kN/m³ because loads are forces: concrete is about 24 kN/m³, compacted soil about 18.
In US practice the same numbers appear in pounds per cubic foot: concrete is about 150 lbf/ft³.