Kilogram per Cubic Meter to Pound per Cubic Foot Converter
Converts kilogram per cubic meter to pound per cubic foot (kg/m³ to lb/ft³) and back. The conversion factor is shown below every result.
How to Convert Kilogram per Cubic Meter to Pound per Cubic Foot
What Is a Kilogram per Cubic Meter?
Kilogram per cubic meter (kg/m³) is the SI unit of density.
What Is a Pound per Cubic Foot?
Pound per cubic foot (lb/ft³) is a US customary unit of density equal to exactly 16.018463373960138 kg/m³.
Common Kilogram per Cubic Meter to Pound per Cubic Foot Reference Points
Real-world reference values for quick sanity checks.
| Item | Kilogram per Cubic Meter (kg/m³) | Pound per Cubic Foot (approx.) |
|---|---|---|
| Dry air at sea level (approx.) | 1.2 kg/m³ | 0.075 lb/ft³ |
| Softwood, e.g. pine (typical, varies by moisture) | 500 kg/m³ | 31.21 lb/ft³ |
| Hardwood, e.g. oak (typical, varies by moisture) | 750 kg/m³ | 46.82 lb/ft³ |
| Water's density | 1000 kg/m³ | 62.43 lb/ft³ |
| Normal-weight concrete (approx.) | 2400 kg/m³ | 149.83 lb/ft³ |
| Aluminum's density | 2700 kg/m³ | 168.55 lb/ft³ |
| Structural steel (approx.) | 7850 kg/m³ | 489.96 lb/ft³ |
| Reference values are illustrative approximations for common items, not measured specifications. | ||
Where This Conversion Actually Shows Up
Density conversions come up most often in materials and construction contexts where specs are written in one unit system and the working drawings or supplier catalog use the other. Soil density in geotechnical reports, aggregate and concrete mix specifications, and structural material datasheets are frequently published in kg/m³ internationally, while US engineering and construction references commonly use lb/ft³.
Woodworking and lumber specs are a common case too: species density (how heavy a given board actually is, which affects everything from shipping weight to how a joint will hold under load) is often listed in kg/m³ in wood-science references and needs converting to compare against US lumber supplier data in lb/ft³.
Why Wood Density Is Given as a Range, Not a Fixed Number
Unlike a manufactured material such as steel or aluminum, wood density genuinely varies, by species, by growing conditions, and significantly by moisture content. A "typical" softwood or hardwood figure is a reasonable planning estimate, not a specification you'd rely on for a structural calculation. If you have an actual measured or supplier-provided density figure for your specific material, use that instead of a typical value from a table.
Kilogram per Cubic Meter to Pound per Cubic Foot Conversion Table
| Kilogram per Cubic Meter (kg/m³) | Pound per Cubic Foot (lb/ft³) |
|---|---|
| 100 kg/m³ | 6.242796 lb/ft³ |
| 500 kg/m³ | 31.21398 lb/ft³ |
| 1000 kg/m³ | 62.427961 lb/ft³ |
| 2000 kg/m³ | 124.855921 lb/ft³ |
| 2700 kg/m³ | 168.555494 lb/ft³ |
| 5000 kg/m³ | 312.139803 lb/ft³ |
| Source: NIST SP 811 (1 lb/ft³ = 16.018463373960138 kg/m³ exactly) | |
Frequently Asked Questions
How do I convert kg/m³ to lb/ft³?
Multiply the kg/m³ value by 0.0624279606. For example, 1,000 kg/m³ × 0.0624279606 = 62.428 lb/ft³.
What is water's density in both units?
Water is approximately 1,000 kg/m³, which converts to about 62.428 lb/ft³, a commonly cited reference point in both metric and US customary engineering contexts.
Why isn't the factor a round number?
It combines two independent exact definitions, the pound-to-kilogram ratio and the foot-to-meter ratio cubed (since volume scales as length cubed), neither of which is round on its own.
Related Density Converters
A good measuring tool marked in both kg/m³ and lb/ft³ removes the guesswork at the point of use.