kg/m³ to lb/ft³

Every US concrete mix design lives on this conversion. Water is 62.4 lb/ft³. Normal-weight concrete is about 150 lb/ft³. A metric spec sheet says 2,400 kg/m³; the US batch plant wants 150 lb/ft³. The bridge is 16.018463 — the 1959 pound divided by the 1959 foot, cubed.

By EnginStack Engineering Team | Verified by engineers, built on NIST metrology standards About →
kg/m³
1000 lb/ft³
1000 kg/m³ = 1000 lb/ft³ 1000 lb/ft³ = 1000 kg/m³

Source: NIST SP 811 and the 1959 yard-and-pound agreement (0.9144 m, 0.45359237 kg). Every decimal place in the factor above is a defined constant, not a measurement.

kg/m³ to lb/ft³

Every US concrete mix design lives on this conversion. Water is 62.4 lb/ft³. Normal-weight concrete is about 150 lb/ft³. A metric spec sheet says 2,400 kg/m³; the US batch plant wants 150 lb/ft³. The bridge is 16.018463 — the 1959 pound divided by the 1959 foot, cubed.

lb/ft³ = kg/m³ × 0.06242796059
1 kg/m³ = 0.06242796059 lb/ft³ — the 1959 pound over the 1959 foot, cubed
The factor is exact — derived from SI definitions and the 1959 yard/pound agreement.

Common kg/m³ to lb/ft³ Conversions

kg/m³lb/ft³Material / context
1 kg/m³0.0624 lb/ft³The definitional anchor.
1.225 kg/m³0.0765 lb/ft³Air at sea level.
600 kg/m³37.5 lb/ft³Dry pine wood.
1,000 kg/m³62.4 lb/ft³Water — the US construction anchor.
1,600 kg/m³99.9 lb/ft³Lightweight concrete.
2,400 kg/m³149.8 lb/ft³Normal concrete.
7,850 kg/m³490 lb/ft³Carbon steel.

Engineering Context

Density links the mass and volume families on this site — it is their ratio. For the mass numerator, the kg to g and lbs to kg converters carry the same 1959 constants that appear here; for the volume denominator, the liters to mL and cubic feet to cubic meters pages supply the cubed lengths. The density hub collects all ten converters in this family.

More: Lb Ft3 To Kg M3 · Kg M3 To G Cm3 · G Cm3 To Lb Ft3 · Density

Related Unit Converters

Lb Ft3 To Kg M3 Kg M3 To G Cm3 G Cm3 To Lb Ft3 Density Density Converters

Frequently Asked Questions

Why is water 62.4 lb/ft³?

Because a cubic foot of water weighs 62.4 pounds — a consequence of the 1959 pound and foot definitions, cubed. The exact value is 62.427961 lb/ft³ at maximum density. US engineers memorize 62.4 the way metric engineers memorize 1,000; both are the same water.

Is concrete really 150 lb/ft³?

Normal-weight concrete is commonly specified at 150 lb/ft³ (about 2,400 kg/m³). Lightweight concrete drops to 90-115 lb/ft³, and the mix density is a structural input — changing it changes the dead load and the footing size.

What about the 1959 foot?

The foot was defined as exactly 0.3048 meters by the 1959 agreement. Density cubes it: one cubic foot is exactly 0.028316846592 cubic meters. That's where the 16.018463 comes from.