🧱 lb/ft³ to lb/in³ — Pound/Cubic Foot to Pound/Cubic Inch Converter

Convert density units — kg/m³, g/cm³, lb/ft³, lb/in³ and more.

1 unit =
From
To
Formula 1 lb/ft³ = 0.0005787 lb/in³
UnitNameValue
kg/m³ Kilogram/Cubic Meter 16.0185
g/cm³ Gram/Cubic Centimeter 0.0160185
kg/L Kilogram/Liter 0.0160185
lb/in³ Pound/Cubic Inch 0.00057870513
oz/in³ Ounce/Cubic Inch 0.0092593021
t/m³ Tonne/Cubic Meter 0.0160185

Quick Answer

Formula: lb/in³ = lb/ft³ × 0.0005787

Multiply any lb/ft³ value by 0.0005787 to get lb/in³.

Reverse: lb/ft³ = lb/in³ × 1728

Worked Examples

0.001 lb/ft³
0.001 lb/ft³ × 0.0005787 = 5.7871e-7 lb/in³
Very low density.
1 lb/ft³
1 lb/ft³ × 0.0005787 = 0.0005787 lb/in³
1 unit reference.
1000 lb/ft³
1000 lb/ft³ × 0.0005787 = 0.5787 lb/in³
Water density range.
7850 lb/ft³
7850 lb/ft³ × 0.0005787 = 4.543 lb/in³
Steel density range.

lb/ft³ to lb/in³ Conversion Table

Common materials — factor: 1 lb/ft³ = 0.0005787 lb/in³

lb/ft³ (lb/ft³)lb/in³ (lb/in³)Material
0.001 lb/ft³5.787e-07 lb/in³Vacuum
0.01 lb/ft³5.787e-06 lb/in³Low pressure gas
0.1 lb/ft³5.787e-05 lb/in³Very light foam
0.0765 lb/ft³4.427e-05 lb/in³Air
1 lb/ft³0.0005787 lb/in³Light insulation
10 lb/ft³0.005787 lb/in³Rigid foam
43.7 lb/ft³0.02529 lb/in³Wood (oak)
57.4 lb/ft³0.03322 lb/in³Concrete light
62.4 lb/ft³0.03611 lb/in³Water
64 lb/ft³0.03704 lb/in³Seawater
100 lb/ft³0.05787 lb/in³Dense concrete
167 lb/ft³0.09664 lb/in³Aluminum
490 lb/ft³0.2836 lb/in³Steel
708 lb/ft³0.4097 lb/in³Lead
1204 lb/ft³0.6968 lb/in³Gold

Mental Math Tricks

Exact factor

1 lb/ft³ = 0.0005787 lb/in³.

Water anchor

Water = 1,000 kg/m³ = 1 g/cm³ = 1 kg/L = 62.4 lb/ft³ = 0.0361 lb/in³.

Reverse

Multiply result by 1728 to recover the original lb/ft³ value.

Who Uses This Conversion?

Materials Engineer

Compares material densities to optimize weight-to-strength ratios in product design.

Civil/Structural Engineer

Calculates dead loads from material densities for structural design in kg/m³ and lb/ft³.

Aerospace Engineer

Selects lightweight materials (aluminum, titanium, composites) based on density in g/cm³ or lb/in³.

Petroleum Engineer

Measures crude oil and drilling fluid density in kg/m³ or lb/ft³ for reservoir engineering.

Geotechnical Engineer

Measures soil and rock bulk density in t/m³ for foundation and slope stability analysis.

Chemical Engineer

Uses density in g/cm³ for solution concentration, specific gravity, and process design calculations.

Frequently Asked Questions

About lb/ft³ and lb/in³

lb/ft³ (lb/ft³)

Pounds per cubic foot (lb/ft³) is the standard density unit in US engineering and construction. One lb/ft³ equals approximately 16.018 kg/m³. It is used for structural materials, soil, insulation, and HVAC calculations in American practice.

Common lb/ft³ values: air = 0.0765 lb/ft³, water = 62.4 lb/ft³, concrete = 145–150 lb/ft³, structural steel = 490 lb/ft³, wood varies 20–50 lb/ft³. ASHRAE tables for HVAC use lb/ft³ for air and refrigerant densities.

Interesting fact: Aerogel, the world's least dense solid material, has a density of about 0.1–1 lb/ft³ (1.6–16 kg/m³). It is primarily composed of air and can support thousands of times its own weight.

lb/in³ (lb/in³)

Pounds per cubic inch (lb/in³) is used in aerospace, precision machining, and materials engineering where compact unit sizes are practical. One lb/in³ equals 27,679.9 kg/m³.

lb/in³ is standard in US aerospace for specifying material density in structural weight calculations: aluminum = 0.098 lb/in³, titanium = 0.160 lb/in³, steel = 0.284 lb/in³. The unit is preferred because aircraft structural calculations often work in inch-pound units.

Interesting fact: The density of uranium is 0.69 lb/in³ (19,100 kg/m³), making it about 2.4 times denser than steel. This high density — combined with its nuclear properties — makes it valuable for radiation shielding and as kinetic energy penetrators.

About lb/ft³ to lb/in³ Conversion

Converting lb/ft³ to lb/in³ is common in materials science, engineering, and manufacturing. SI units (kg/m³, g/cm³) are standard in scientific and metric engineering contexts, while Imperial units (lb/ft³, lb/in³) are used in US construction and aerospace. Water at 4°C = 62.43 lb/ft³ = 0.03613 lb/in³ — a universal anchor for density comparisons.

Exact factor: 1 lb/ft³ = 0.0005787 lb/in³. Reverse: 1 lb/in³ = 1728 lb/ft³.

All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.