kg/m³ to kN/m³ and kN/m³ to kg/m³ Density Converter

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Density Converter

kg/m³, kN/m³, t/m³, g/cm³, lb/ft³, oz/in³ — with material presets

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2400 kg/m³
=
23.536 kN/m³

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Material kg/m³ kN/m³ t/m³ lb/ft³

FAQ

How do I convert kg/m³ to kN/m³?
Multiply the value in kg/m³ by gravitational acceleration (g = 9.80665 m/s²) and divide by 1000. For example, 2400 kg/m³ × 9.80665 / 1000 ≈ 23.536 kN/m³. A common rounded shortcut uses g ≈ 10, which gives 1000 kg/m³ ≈ 10 kN/m³.
What is the difference between density and unit weight?
Density (mass per volume, kg/m³ or g/cm³) measures how much matter fits in a given space. Unit weight (kN/m³ or lb/ft³) measures the gravitational force per volume. Unit weight equals density multiplied by g. Structural engineers usually work in kN/m³, while physicists and chemists prefer kg/m³ or g/cm³.
How is 1 g/cm³ related to 1000 kg/m³?
1 g/cm³ equals exactly 1000 kg/m³, because 1 cm³ = 1 mL and 1 g = 0.001 kg. Water at 4°C has a density of 1.000 g/cm³ = 1000 kg/m³ = 1 t/m³ = 9.807 kN/m³.
What is the unit weight of concrete?
Normal-weight concrete is usually taken as 2400 kg/m³ (23.5 kN/m³ or 150 lb/ft³). Reinforced concrete is slightly heavier — about 2500 kg/m³ (24.5 kN/m³). Lightweight structural concrete ranges from 1600 to 1900 kg/m³.
How do I convert lb/ft³ to kg/m³?
1 lb/ft³ equals about 16.0185 kg/m³. So a material listed at 150 lb/ft³ has a density of approximately 2403 kg/m³. The reverse factor: 1 kg/m³ ≈ 0.06243 lb/ft³.
Why does my converter use g = 9.80665 instead of 9.81?
9.80665 m/s² is the internationally adopted standard value of gravity (CGPM 1901). Using 9.81 introduces a small rounding error (<0.04%). For most engineering calculations both values are acceptable, but international standards documents and ISO references use 9.80665.

All conversions use the standard gravity g = 9.80665 m/s².

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About this density converter

This converter switches density and unit weight between seven units: kg/m³, t/m³, g/cm³, g/mL, kN/m³, lb/ft³, and oz/in³. Pick a from-unit and a to-unit, type any value, and read every other unit at the same time. The kg/m³ ↔ kN/m³ conversion uses the standard gravity g = 9.80665 m/s², so 1000 kg/m³ ≈ 9.807 kN/m³.

A built-in material database covers more than 50 entries — water, concretes, sand, gravel, soils, brick, asphalt, structural metals, woods, insulation, and several liquids — so you can pick a material and instantly see its density in every unit. The reference table at the bottom shows the most common construction materials in kg/m³, kN/m³, t/m³, and lb/ft³ for quick comparison.

Example: normal-weight concrete at 2400 kg/m³ corresponds to about 23.54 kN/m³, 2.4 t/m³, and 149.83 lb/ft³.