About

Converting volume to weight requires knowing the material's density. A cubic foot of feathers and a cubic foot of lead occupy identical space but differ in mass by a factor of roughly 700. This calculator applies W = V × ρ using vetted density constants from engineering handbooks (ASTM, USDA grain standards, NIST material property databases). Errors in volume-to-weight conversion propagate directly into shipping cost estimates, structural load calculations, and regulatory compliance reports. A 5% density error on a 40-foot container of aggregate translates to multiple tons of miscalculated freight.

The tool includes 50+ pre-loaded materials spanning metals, liquids, soils, woods, grains, and construction aggregates. Each density value represents a typical midpoint. Real-world density varies with moisture content, temperature, compaction, and alloy composition. For granular materials, the listed values assume loose (uncompacted) bulk density unless noted. Pro tip: for soil and gravel, field-measured densities can differ 15 - 25% from reference tables depending on moisture and compaction level.

Formulas

The fundamental relationship between volume, density, and weight governs this conversion. Weight is the product of the volume occupied and the material's density.

W = V × ρ

Where W = weight in lb, V = volume in ft³, and ρ = density in lb/ft³.

To convert density from metric units:

ρ_lb/ft³ = ρ_kg/m³ × 0.062428

Where 0.062428 is the conversion factor from kg/m³ to lb/ft³. For converting the result to other weight units: 1 lb = 16 oz = 0.4536 kg = 0.0005 short tons.

Volume equivalencies: 1 ft³ = 1728 in³ = 7.481 US gal = 28.317 L = 0.02832 m³.

Reference Data

Material	Density (lb/ft³)	Density (kg/m³)	Category	Notes
Water (pure, 4°C)	62.43	1000	Liquid	Reference standard
Seawater	64.0	1025	Liquid	~3.5% salinity
Gasoline	46.8	750	Liquid	API gravity ~58
Diesel Fuel	53.1	850	Liquid	No. 2 diesel
Motor Oil (SAE 30)	56.2	900	Liquid	At 15°C
Milk (whole)	64.2	1028	Liquid	~3.5% fat
Honey	88.9	1420	Liquid	Varies with moisture
Steel (carbon)	490	7850	Metal	AISI 1020
Aluminum (6061)	169	2710	Metal	T6 temper
Copper	559	8960	Metal	Pure, annealed
Lead	708	11340	Metal	Pure
Gold	1206	19320	Metal	24 karat
Iron (cast)	450	7200	Metal	Gray cast iron
Brass	534	8550	Metal	Yellow brass
Titanium	281	4507	Metal	Grade 5 (Ti-6Al-4V)
Zinc	445	7130	Metal	Pure
Concrete (reinforced)	150	2400	Construction	Typical structural
Concrete (lightweight)	100	1600	Construction	Expanded aggregate
Asphalt	145	2320	Construction	Hot mix
Brick (common)	120	1920	Construction	Solid clay
Glass (window)	162	2600	Construction	Soda-lime
Granite	168	2690	Stone	Average
Marble	169	2710	Stone	Average
Limestone	155	2480	Stone	Average quarried
Sandstone	137	2200	Stone	Average
Sand (dry)	100	1600	Aggregate	Loose
Sand (wet)	120	1920	Aggregate	Saturated
Gravel (loose)	95	1522	Aggregate	Uncompacted
Gravel (compacted)	125	2000	Aggregate	Vibrated
Topsoil (dry)	75	1200	Soil	Loose, dry
Topsoil (wet)	100	1600	Soil	Moist
Clay (dry)	100	1600	Soil	Unfired
Clay (wet)	110	1760	Soil	Saturated
Mulch (wood)	20	320	Organic	Loose, dry
Compost	40	640	Organic	Mature, loose
Peat Moss	15	240	Organic	Dry, loose
Oak (red)	44	705	Wood	Air-dried (12% MC)
Pine (yellow)	36	577	Wood	Air-dried
Maple (sugar)	44	705	Wood	Air-dried
Cedar (western red)	23	368	Wood	Air-dried
Balsa	9	144	Wood	Air-dried
Plywood	36	577	Wood	Softwood, typical
Wheat (grain)	48.5	777	Grain	USDA test weight
Corn (shelled)	44.8	718	Grain	USDA test weight
Rice (rough)	36	577	Grain	Paddy
Soybeans	48	769	Grain	USDA test weight
Sugar (granulated)	53	849	Food	Loose
Flour (all-purpose)	37	593	Food	Unsifted
Salt (table)	75	1200	Food	Fine grain
Ice	57.2	917	Solid	At 0°C
Snow (fresh)	5	80	Other	Freshly fallen
Snow (packed)	20	320	Other	Compacted
Air (sea level, 20°C)	0.075	1.2	Gas	At 1 atm

Frequently Asked Questions

Moisture adds direct mass without significantly changing volume in rigid materials like wood. A piece of oak at 12% moisture content has a density of approximately 44 lb/ft³, but at 30% (green, freshly cut) it can reach 55-60 lb/ft³. For soils, the effect is even more dramatic: dry topsoil averages 75 lb/ft³ while saturated topsoil can exceed 100 lb/ft³. Always specify moisture condition when converting volume to weight for these materials. The densities in this calculator assume air-dried conditions for wood and loose/dry conditions for soils unless otherwise noted.

Granular materials like sand and gravel contain air voids between particles. Loose (uncompacted) gravel has roughly 35-40% void space, yielding about 95 lb/ft³. After mechanical compaction (vibration or tamping), voids collapse and density increases to approximately 125 lb/ft³ - a 30% increase in weight for the same volume. Shipping and construction specifications typically reference either bulk (loose) or compacted density. Using the wrong one causes significant errors in load calculations and material ordering.

Yes, but gas density is highly dependent on temperature and pressure. The listed air density of 0.075 lb/ft³ applies at sea level (1 atm) and 20°C. At higher altitudes or temperatures, density drops. For compressed gases in cylinders, the effective density can be orders of magnitude higher than atmospheric values. This calculator uses standard atmospheric conditions. For non-standard conditions, apply the ideal gas law correction or enter a custom density value.

This calculator outputs weight in pounds-force (lbf), which assumes standard Earth gravity (g = 32.174 ft/s²). On Earth's surface, the numerical difference between mass in pound-mass (lbm) and weight in pound-force (lbf) is negligible for practical purposes. The density values listed are technically mass densities (lbm/ft³), and multiplying by volume gives mass, which equals weight at 1g. For engineering on other planets or in centrifuges, a separate gravitational correction is required.

The metal densities represent pure or standard alloy compositions at room temperature (20°C). Pure copper is listed at 559 lb/ft³ (8960 kg/m³), which matches NIST reference data. However, commercial alloys vary: bronze ranges from 500-550 lb/ft³ depending on tin content, and stainless steel grades span 490-510 lb/ft³. Temperature also matters - steel at 800°C has roughly 3% lower density due to thermal expansion. For critical structural or cost calculations, use the specific alloy datasheet value rather than generic figures.

Divide the result in pounds by 2204.62 to obtain metric tonnes (t). For example, 10,000 lb ÷ 2204.62 = 4.536 t. For US short tons, divide by 2000. For long (imperial) tons, divide by 2240. The calculator provides results in pounds, kilograms, ounces, and short tons simultaneously. Shipping containers typically have a maximum payload of 44,000-48,000 lb (20-22 t), so cross-reference your converted weight against container limits.