How do you convert cubic feet to pounds?

You cannot convert cubic feet to pounds without knowing the density of the material, because cubic feet measures volume while pounds measures weight (mass). The formula is: Weight (lb) = Volume (ft³) x Density (lb/ft³). For example, water has a density of approximately 62.43 lb/ft³, so 5 cubic feet of water weighs 5 x 62.43 = 312.15 lb. Different materials have very different densities: concrete is about 150 lb/ft³, dry sand is about 100 lb/ft³, and pine timber is about 31 lb/ft³.

How many pounds is 1 cubic foot of water?

One cubic foot of water weighs approximately 62.43 pounds (or 28.32 kg) at standard temperature (4°C / 39°F). This is the most common reference density for volume-to-weight conversions. At typical room temperature (20°C), water is slightly less dense at about 62.30 lb/ft³, but 62.43 lb/ft³ is the standard figure used in most calculations.

How many pounds is 1 cubic foot of concrete?

One cubic foot of standard ready-mix concrete weighs approximately 150 pounds (68 kg). This figure is used in most structural engineering calculations. Lightweight concrete can weigh as little as 90 lb/ft³, and high-density concrete used for radiation shielding can exceed 200 lb/ft³. The standard 150 lb/ft³ (2,400 kg/m³) figure applies to normal-weight concrete made with sand, gravel, and Portland cement.

Cubic Feet to Pounds Calculator

Convert cubic feet to pounds for water, concrete, soil, gravel, sand, steel, wood, and more. Because pounds measure weight and cubic feet measure volume, the conversion depends on the density of the material. Select a preset material or enter a custom density to get the weight instantly.

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Reviewed June 2026 Material densities based on standard engineering reference values (ASTM, ACI 318, AISC).

1. Volume

Volume in cubic feet (ft³)

ft³

2. Material / Density

Material

Conversion Result

Weight in Pounds
-
lb

Weight in Kilograms

Weight in Tonnes

metric tonnes

Weight in US Tons

short tons (2,000 lb)

Conversion Breakdown

Volume-

Material-

Density-

Formulaft³ × lb/ft³

Weight in pounds-

Weight in All Units

Pounds (lb)-

Ounces (oz)-

Kilograms (kg)-

Grams (g)-

Metric tonnes (t)-

Short tons (US)-

Result: Enter a volume above to see the weight.

Weight per Cubic Foot by Material

Material	Density (lb/ft³)	5 ft³ weighs	10 ft³ weighs	1 yd³ (27 ft³) weighs

How to Convert Cubic Feet to Pounds

Volume (cubic feet) measures the amount of space a material occupies. Weight (pounds) measures the force of gravity acting on the material's mass. To convert between the two, you need the material's density, which tells you how many pounds fit in one cubic foot.

The formula is straightforward:

Weight (lb) = Volume (ft³) × Density (lb/ft³)

For example, if you have 5 cubic feet of water and water weighs 62.43 lb/ft³:

Weight = 5 × 62.43 = 312.15 lb

This is why you cannot convert cubic feet to pounds without specifying the material. Five cubic feet of steel weighs about 2,450 lb, while five cubic feet of pine timber weighs only about 155 lb.

Common Material Densities in lb/ft³

Material	Density (lb/ft³)	Density (kg/m³)	Notes
Water	62.43	1,000	Standard at 4°C
Concrete, normal weight	150	2,400	Ready-mix, cured
Sand, dry	100	1,600	Loosely packed
Sand, wet	110	1,760	Saturated
Soil, loose dry	75	1,200	Varies significantly
Soil, packed	95	1,520	Compacted fill
Gravel, dry	100	1,600	Mixed aggregate
Gravel, wet	120	1,920	Saturated aggregate
Steel	490	7,849	Structural steel
Aluminium	168	2,700	Pure aluminium
Pine timber	31	497	Dry radiata pine
Oak timber	45	721	Dry hardwood
Brick	94	1,506	Standard clay brick
Asphalt	87	1,395	Compacted road mix

Converting Between Cubic Feet and Cubic Yards

One cubic yard equals 27 cubic feet (3 ft × 3 ft × 3 ft). If your volume is quoted in cubic yards, multiply by 27 before applying the density. For example, one cubic yard of concrete (27 ft³ × 150 lb/ft³) weighs 4,050 lb (about 2 short tons), which is why concrete delivery trucks are rated by the cubic yard.

Converting Pounds to Kilograms and Tonnes

Once you have the weight in pounds, you can convert to metric units:

Kilograms: divide by 2.20462 (or multiply by 0.453592)
Metric tonnes: divide by 2,204.62
Short tons (US): divide by 2,000
Long tons (UK): divide by 2,240

For example, 312.15 lb of water converts to 141.59 kg, or 0.14 metric tonnes.

Practical Uses

Knowing the weight of a volume of material is useful in many real-world situations. Builders need to know whether a floor or trailer can handle the load from a pile of gravel or bags of concrete. Truckers need to stay within load limits. Aquarium owners calculate the weight of water before placing a tank on a shelf. Landscapers estimate how many cubic metres of soil a ute can carry before exceeding its payload. This calculator handles all of these scenarios by letting you choose the right material density.

Related Calculators

Method: Weight (lb) = Volume (ft³) × Density (lb/ft³). Density values are standard engineering reference figures from ASTM, ACI 318, and the Engineering Toolbox. Material densities vary depending on moisture content, compaction, and grade; the values shown are typical averages.

Material densities are approximate averages. Actual weight depends on moisture content, compaction, grade, and temperature. For structural or load-bearing calculations, consult a qualified engineer and verify material specifications with your supplier.

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