Pounds per Cubic Foot to Kg/m³ Converter 2026 | lb/ft³ to kg/m³

Pounds per Cubic Foot to Kg/m³ Converter 2026

Convert lb/ft³ to kg/m³ and Other Density Units

Accurate Density Conversion Calculator

Pounds per cubic foot (lb/ft³) and kilograms per cubic meter (kg/m³) are standard density measurements used across different industries and regions. Our pounds per cubic foot to kg/m³ converter provides precise conversions for construction materials, engineering calculations, and scientific applications following NIST standards in 2026.

One pound per cubic foot equals exactly 16.018463 kilograms per cubic meter. Understanding density conversions is essential for material specifications, structural engineering, and international project collaboration. For comprehensive measurement standards, visit Bureau International des Poids et Mesures.

⚖️ Density Converter Calculator

Convert between lb/ft³, kg/m³, and other density units

Density Conversion

Input Unit

Density Value

Output Unit

lb/ft³ to kg/m³ Conversion Table 2026

This comprehensive conversion table provides quick reference values for converting pounds per cubic foot to kilograms per cubic meter. The conversion factor is based on international standards where 1 lb/ft³ = 16.018463 kg/m³, as defined by NIST and accepted worldwide.

Common Density Conversions

lb/ft³	kg/m³	g/cm³	Common Materials
1 lb/ft³	16.02 kg/m³	0.016 g/cm³	Cork, foam insulation
5 lb/ft³	80.09 kg/m³	0.080 g/cm³	Expanded polystyrene
10 lb/ft³	160.18 kg/m³	0.160 g/cm³	Softwood, balsa
25 lb/ft³	400.46 kg/m³	0.400 g/cm³	Pine, cedar wood
40 lb/ft³	640.74 kg/m³	0.641 g/cm³	Hardwood, oak
62.4 lb/ft³	999.55 kg/m³	1.000 g/cm³	Water (at 4°C)
75 lb/ft³	1,201.38 kg/m³	1.201 g/cm³	Dense hardwood
100 lb/ft³	1,601.85 kg/m³	1.602 g/cm³	Light aggregate
150 lb/ft³	2,402.77 kg/m³	2.403 g/cm³	Concrete, brick
165 lb/ft³	2,643.05 kg/m³	2.643 g/cm³	Standard concrete
200 lb/ft³	3,203.69 kg/m³	3.204 g/cm³	Dense stone
490 lb/ft³	7,849.05 kg/m³	7.849 g/cm³	Steel, iron
556 lb/ft³	8,906.27 kg/m³	8.906 g/cm³	Copper
708 lb/ft³	11,341.07 kg/m³	11.341 g/cm³	Lead

Water Density

lb/ft³ 62.4

kg/m³ 999.55

g/cm³ 1.000

Concrete Density

lb/ft³ 165

kg/m³ 2,643.05

g/cm³ 2.643

Steel Density

lb/ft³ 490

kg/m³ 7,849.05

g/cm³ 7.849

Copper Density

lb/ft³ 556

kg/m³ 8,906.27

g/cm³ 8.906

Understanding Density Units

Density measures mass per unit volume and is fundamental to material science, engineering, and construction. Different unit systems use various density measurements, with lb/ft³ common in North America and kg/m³ as the SI standard worldwide.

Pounds per Cubic Foot (lb/ft³)

Symbol: lb/ft³ or pcf

System: Imperial/US customary units

Usage: North American construction, lumber industry, aggregate materials

Conversion: 1 lb/ft³ = 16.018463 kg/m³

Common Range: 1-200 lb/ft³ for construction materials

Kilograms per Cubic Meter (kg/m³)

Symbol: kg/m³

System: International System (SI)

Usage: International standards, engineering, scientific applications

Conversion: 1 kg/m³ = 0.062428 lb/ft³

Common Range: 10-8,000 kg/m³ for construction materials

Grams per Cubic Centimeter (g/cm³)

Symbol: g/cm³ or g/cc

System: CGS unit system

Usage: Laboratory measurements, material science, quality control

Conversion: 1 g/cm³ = 1,000 kg/m³ = 62.428 lb/ft³

Reference: Water = 1.0 g/cm³ at 4°C

Pounds per Cubic Inch (lb/in³)

Symbol: lb/in³

System: Imperial/US customary units

Usage: Small volume measurements, metal stock, precision engineering

Conversion: 1 lb/in³ = 1,728 lb/ft³ = 27,679.9 kg/m³

Common Range: 0.01-0.5 lb/in³ for most materials

Specific Gravity (SG)

Symbol: SG (dimensionless)

Definition: Ratio of material density to water density

Usage: Material identification, quality control, buoyancy calculations

Reference: Water SG = 1.0 (at 4°C)

Calculation: SG = material density ÷ water density

Tonnes per Cubic Meter (t/m³)

Symbol: t/m³ or MT/m³

System: Metric tonne system

Usage: Heavy materials, mining, bulk commodities

Conversion: 1 t/m³ = 1,000 kg/m³ = 62.428 lb/ft³

Note: Numerically equal to g/cm³

Conversion Formulas and Calculations

Accurate density conversions require understanding the relationships between different unit systems. Our lb/ft³ to kg/m³ converter uses precise conversion factors derived from fundamental unit definitions.

📐 Primary Density Conversion Formulas:

lb/ft³ to kg/m³: kg/m³ = lb/ft³ × 16.018463
kg/m³ to lb/ft³: lb/ft³ = kg/m³ × 0.062428
g/cm³ to kg/m³: kg/m³ = g/cm³ × 1,000
lb/in³ to lb/ft³: lb/ft³ = lb/in³ × 1,728
Specific Gravity: SG = density ÷ 1,000 kg/m³
lb/ft³ to g/cm³: g/cm³ = lb/ft³ × 0.016018

Example Calculations

Example 1: Concrete Density

Given: Concrete density = 150 lb/ft³

Calculate: Density in kg/m³

Solution: 150 × 16.018463 = 2,402.77 kg/m³

Result: Standard concrete = 2,403 kg/m³

Example 2: Steel Density

Given: Steel = 7,850 kg/m³

Calculate: Density in lb/ft³

Solution: 7,850 × 0.062428 = 490.06 lb/ft³

Result: Steel ≈ 490 lb/ft³

Example 3: Wood Density

Given: Oak wood = 45 lb/ft³

Calculate: Specific gravity

Solution: 45 × 16.018463 = 720.83 kg/m³, SG = 720.83/1000 = 0.72

Result: Oak SG = 0.72

Example 4: Aggregate Weight

Given: 10 cubic yards @ 100 lb/ft³

Calculate: Total weight in tonnes

Solution: 10 yd³ × 27 ft³/yd³ × 100 lb/ft³ ÷ 2,204.62 = 12.25 tonnes

Result: 12.25 metric tonnes

Construction Material Densities

Understanding material densities is critical for structural calculations, load estimates, and material specifications in construction and engineering projects following ASTM standards.

Concrete Types

Lightweight: 90-115 lb/ft³ (1,440-1,840 kg/m³)

Normal Weight: 140-150 lb/ft³ (2,240-2,400 kg/m³)

Reinforced: 150-160 lb/ft³ (2,400-2,560 kg/m³)

Heavyweight: 200-300 lb/ft³ (3,200-4,800 kg/m³)

Aggregates

Sand (dry): 90-110 lb/ft³ (1,440-1,760 kg/m³)

Gravel: 95-105 lb/ft³ (1,520-1,680 kg/m³)

Crushed Stone: 100-115 lb/ft³ (1,600-1,840 kg/m³)

Limestone: 160-170 lb/ft³ (2,560-2,720 kg/m³)

Wood Products

Softwood: 20-35 lb/ft³ (320-560 kg/m³)

Hardwood: 35-60 lb/ft³ (560-960 kg/m³)

Plywood: 30-45 lb/ft³ (480-720 kg/m³)

Engineered Wood: 35-50 lb/ft³ (560-800 kg/m³)

Metals

Aluminum: 168 lb/ft³ (2,690 kg/m³)

Steel: 490 lb/ft³ (7,850 kg/m³)

Copper: 556 lb/ft³ (8,906 kg/m³)

Lead: 708 lb/ft³ (11,340 kg/m³)

Masonry

Brick (solid): 120-125 lb/ft³ (1,920-2,000 kg/m³)

Concrete Block: 85-130 lb/ft³ (1,360-2,080 kg/m³)

Stone (natural): 150-175 lb/ft³ (2,400-2,800 kg/m³)

Mortar: 115-125 lb/ft³ (1,840-2,000 kg/m³)

Insulation

Fiberglass: 0.5-1.5 lb/ft³ (8-24 kg/m³)

Polystyrene Foam: 1-3 lb/ft³ (16-48 kg/m³)

Spray Foam: 2-4 lb/ft³ (32-64 kg/m³)

Mineral Wool: 1.5-3 lb/ft³ (24-48 kg/m³)

Applications in Engineering and Construction

Density conversions are essential across numerous engineering disciplines and construction applications. Accurate conversions ensure proper structural calculations, material specifications, and project compliance.

✅ Key Applications:

Structural Engineering: Load calculations, dead load determination, foundation design
Material Specifications: Concrete mix design, aggregate selection, quality control
Shipping and Logistics: Weight calculations, freight classification, cargo planning
Cost Estimation: Material quantity takeoffs, pricing per weight, budget planning
International Projects: Converting between imperial and metric specifications
Building Codes: Compliance with local regulations and load requirements

Structural Load Calculations

Material	Density (lb/ft³)	Density (kg/m³)	Typical Use
Concrete (normal)	150	2,403	Slabs, foundations, beams
Reinforced Concrete	155	2,483	Structural elements with rebar
Steel Structural	490	7,850	Beams, columns, plates
Brick Masonry	120	1,922	Walls, facades
Glass	156	2,499	Windows, curtain walls
Asphalt Paving	140	2,243	Roads, parking lots
Soil (compacted)	110	1,762	Fill, backfill, embankments
Gypsum Board	50	801	Interior walls, ceilings

Normal Concrete

Density 150 lb/ft³

Metric 2,403 kg/m³

Use Slabs, foundations

Structural Steel

Density 490 lb/ft³

Metric 7,850 kg/m³

Use Beams, columns

Brick Masonry

Density 120 lb/ft³

Metric 1,922 kg/m³

Use Walls, facades

Specific Gravity and Relative Density

Specific gravity (SG) is a dimensionless ratio comparing material density to water density at standard conditions. This measurement simplifies density comparisons and is widely used in material testing and quality control.

⚠️ Specific Gravity Reference Values:

Water Reference: 1.0 (at 4°C, maximum density)
Materials with SG < 1.0: Float in water (wood, plastics, some aggregates)
Materials with SG > 1.0: Sink in water (metals, concrete, most stones)
Calculation: SG = material density (kg/m³) ÷ 1,000
Alternative: SG = material density (lb/ft³) ÷ 62.4
Temperature Effect: SG values may vary with temperature

Common Specific Gravity Values

Construction Materials

Concrete: SG = 2.3 - 2.5

Granite: SG = 2.6 - 2.7

Limestone: SG = 2.3 - 2.7

Brick: SG = 1.8 - 2.0

Sand: SG = 2.6 - 2.7

Gravel: SG = 2.6 - 2.8

Wood Species

Balsa: SG = 0.1 - 0.2

Pine: SG = 0.4 - 0.6

Oak: SG = 0.6 - 0.9

Teak: SG = 0.6 - 0.7

Ebony: SG = 1.0 - 1.3

Lignum Vitae: SG = 1.2 - 1.3

Common Metals

Aluminum: SG = 2.7

Titanium: SG = 4.5

Iron/Steel: SG = 7.8 - 7.9

Copper: SG = 8.9

Lead: SG = 11.3

Gold: SG = 19.3

Density Conversion FAQs

How do you convert lb/ft³ to kg/m³?

To convert pounds per cubic foot to kilograms per cubic meter, multiply by 16.018463. Formula: kg/m³ = lb/ft³ × 16.018463. For example, 100 lb/ft³ = 100 × 16.018463 = 1,601.85 kg/m³. This conversion factor is derived from the exact definitions of pounds, feet, kilograms, and meters.

What is the density of concrete in lb/ft³ and kg/m³?

Standard concrete density is approximately 150 lb/ft³ or 2,400 kg/m³. Lightweight concrete ranges from 90-115 lb/ft³ (1,440-1,840 kg/m³), while reinforced concrete is about 155 lb/ft³ (2,480 kg/m³). Heavy concrete for radiation shielding can reach 200-300 lb/ft³ (3,200-4,800 kg/m³).

How many kg/m³ is water?

Water has a density of 1,000 kg/m³ (or 1.0 g/cm³) at 4°C, which is its maximum density point. In imperial units, this equals 62.4 lb/ft³. At room temperature (20°C), water density is slightly lower at 998 kg/m³. Water density serves as the reference point for specific gravity calculations.

What is the relationship between density and specific gravity?

Specific gravity (SG) is the ratio of a material's density to water's density at 4°C. Since water = 1,000 kg/m³, you can calculate SG by dividing kg/m³ by 1,000. For example, concrete at 2,400 kg/m³ has SG = 2.4. In imperial units, divide lb/ft³ by 62.4 to get specific gravity.

How do you convert density to weight per volume?

Multiply density by volume to get weight. Formula: Weight = Density × Volume. For example, 5 cubic feet of concrete at 150 lb/ft³ = 750 pounds. In metric: 2 cubic meters at 2,400 kg/m³ = 4,800 kg. Make sure density and volume units match before multiplying.

What is the density of steel in both units?

Steel density is approximately 490 lb/ft³ or 7,850 kg/m³. Stainless steel is slightly denser at 500 lb/ft³ (8,000 kg/m³). Cast iron is about 450 lb/ft³ (7,200 kg/m³). These values are essential for structural calculations and material weight estimates in construction projects.

Why is density important in construction?

Density is critical for structural load calculations, material specifications, cost estimation, and shipping logistics. Engineers use density to calculate dead loads on structures, determine foundation requirements, estimate material quantities, and ensure building code compliance. Accurate density values prevent structural failures and cost overruns.

How do you convert g/cm³ to lb/ft³?

To convert grams per cubic centimeter to pounds per cubic foot, multiply by 62.428. Formula: lb/ft³ = g/cm³ × 62.428. For example, aluminum at 2.7 g/cm³ = 2.7 × 62.428 = 168.56 lb/ft³. Note that g/cm³ is numerically equal to tonnes per cubic meter (t/m³).

What factors affect material density?

Temperature, moisture content, air voids, and compaction affect density. Higher temperatures generally decrease density. Moisture increases density of porous materials like wood and concrete. Air voids reduce density. Compaction increases density by reducing void space. Always specify conditions when reporting density values.

How accurate do density conversions need to be?

For structural engineering, use at least 3-4 significant figures (e.g., 16.02 kg/m³). For rough estimates, 2 significant figures suffice. Building codes typically require accurate density values for load calculations. Quality control testing may need laboratory precision. Always verify density values match project specifications and applicable standards.