What is the density of steel?

7.85 g/cm³, which is 7 850 kg/m³ or 490 lb/ft³. This is the standard figure for carbon and low-alloy steel and is what this site uses for every steel weight calculation. Stainless steel is slightly denser at 7.9 to 8.0 g/cm³ depending on grade, so a stainless part weighs about 1% more than the same part in carbon steel.

How do I convert density to weight?

Multiply density by volume. In metric, kg/m³ × m³ gives kilograms directly — a 2 m × 1 m plate of 10 mm steel is 0.02 m³, and 0.02 × 7 850 = 157 kg. In imperial, lb/ft³ × ft³ gives pounds. Watch the units: density in kg/m³ with volume in cm³ gives an answer a million times too large. The relationship kg/m² = 7.85 × thickness in mm for steel is the shortcut worth memorising.

Why does ice float on water?

Because ice is less dense than liquid water — 0.917 g/cm³ against 1.000 at 4 °C. Most substances are denser as solids than as liquids, but water's hydrogen bonding holds the molecules further apart in the crystal lattice than in the liquid, so freezing expands it by about 9% in volume. This is why water pipes burst when they freeze, and why the 4 °C figure is the point of maximum density.

What is the densest material in the chart?

Tungsten at 19.25 g/cm³ among the engineering metals, and mercury at 13.534 among the liquids. Tungsten's density is why it is used for radiation shielding, counterweights and kinetic penetrators. Lead at 11.34 is the cheaper and more easily worked alternative where the extra density is not essential.

Is specific gravity the same as density?

No — specific gravity is dimensionless and density has units. Specific gravity is the ratio of a material's density to water's, so steel's is 7.85. In the metric system the numbers coincide (7.85 g/cm³ and a specific gravity of 7.85) because water is 1 g/cm³, which is why the two get used interchangeably and why that habit causes errors when working in lb/ft³.

Density Chart

Densities of 56 common materials in g/cm³, kg/m³, lb/ft³ and lb/in³, grouped by class — the reference table for converting a volume into a weight.

Data verified 2026-09-29 · based on n/a — defining value of the metric system, not a revisioned document

Quick Answer

Water is 1.000 g/cm³ (1,000 kg/m³) by definition of the metric system. Carbon steel is 7.85 g/cm³, aluminium 2.70, copper 8.94 and tungsten 19.25 — the densest common engineering metal. Plastics cluster below or just above water; gases are three orders of magnitude lighter.

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Density of Common Materials

Material^[1]	Class^[1]	Density g/cm³^[1]	Density kg/m³^[2]	Density lb/ft³^[3]	Density lb/in³^[3]	Note^[1]
Air (20 °C, 1 atm) #	Gas	0.001205	1.205	0.07523	4.353e-05	The reference for pneumatic and aerodynamic work
Hydrogen #	Gas	8.988e-05	0.08988	0.005611	3.247e-06	Lightest gas; lifting and leak detection
Helium #	Gas	0.0001785	0.1785	0.01114	6.449e-06	Inert lifting gas
Nitrogen #	Gas	0.001251	1.251	0.0781	4.52e-05	The bulk of air by volume
Oxygen #	Gas	0.001429	1.429	0.08921	5.163e-05	Supports combustion; denser than air
Carbon dioxide #	Gas	0.001977	1.977	0.1234	7.142e-05	Denser than air — collects in low spaces
Natural gas (methane) #	Gas	0.000717	0.717	0.04476	2.59e-05	Lighter than air; the basis of gas appliance ratings
Water (4 °C) #	Liquid	1	1000	62.43	0.03613	Maximum density; the defining point of the metric system
Water (20 °C) #	Liquid	0.998	998	62.3	0.03606	Engineering reference temperature
Sea water (3.5% salinity) #	Liquid	1.025	1025	63.99	0.03703	About 2.5% denser than fresh water
Mercury #	Liquid	13.534	13534	844.9	0.4889	The densest common liquid; basis of manometers
Ethanol #	Liquid	0.789	789	49.26	0.0285	Alcohol; less dense than water
Methanol #	Liquid	0.792	792	49.44	0.02861	Industrial solvent and fuel
Glycerol #	Liquid	1.261	1261	78.72	0.04556	Denser and far more viscous than water
Gasoline #	Liquid	0.74	740	46.2	0.02673	Typical figure; varies with grade and temperature
Diesel fuel #	Liquid	0.85	850	53.06	0.03071	Typical figure; varies with grade
Kerosene / jet fuel #	Liquid	0.81	810	50.57	0.02926	Typical figure
Hydraulic oil (ISO 46) #	Liquid	0.876	876	54.69	0.03165	At 15 °C; falls with temperature
Engine oil (SAE 15W-40) #	Liquid	0.875	875	54.62	0.03161	At 15 °C
Magnesium alloy #	Metal	1.74	1740	108.6	0.06286	The lightest structural metal
Aluminium #	Metal	2.7	2700	168.6	0.09754	Pure aluminium; alloys run 2.64–2.83
Titanium #	Metal	4.51	4510	281.6	0.1629	High strength-to-weight; 57% of steel's density
Zinc #	Metal	7.14	7140	445.7	0.2579	Galvanising coating
Cast iron (gray) #	Metal	7.15	7150	446.4	0.2583	Slightly lighter than steel because of the graphite
Carbon steel #	Metal	7.85	7850	490.1	0.2836	The standard figure used throughout this site for steel
Stainless steel 304 #	Metal	7.9	7900	493.2	0.2854	About 0.6% denser than carbon steel
Stainless steel 316 #	Metal	8	8000	499.4	0.289	Denser again, from the molybdenum content
Copper #	Metal	8.94	8940	558.1	0.323	The reference for electrical conductivity
Brass (60/40) #	Metal	8.5	8500	530.6	0.3071	Copper-zinc alloy
Bronze (phosphor) #	Metal	8.8	8800	549.4	0.3179	Copper-tin alloy
Nickel #	Metal	8.9	8900	555.6	0.3215	Basis of many corrosion-resistant alloys
Lead #	Metal	11.34	11340	707.9	0.4097	Dense, soft, used for radiation shielding and ballast
Tungsten #	Metal	19.25	19250	1202	0.6955	The densest common engineering metal
Concrete (normal weight) #	Building material	2.4	2400	149.8	0.08671	Reinforced concrete runs 2.50
Glass (soda-lime) #	Building material	2.5	2500	156.1	0.09032	Window and container glass
Brick (common) #	Building material	1.92	1920	119.9	0.06936	Depends heavily on porosity
Granite #	Building material	2.7	2700	168.6	0.09754	Igneous rock
Sand (dry) #	Building material	1.6	1600	99.88	0.0578	Bulk density, not particle density
Cement (Portland, loose) #	Building material	1.44	1440	89.9	0.05202	Bulk density
Gypsum board #	Building material	0.8	800	49.94	0.0289	Bulk density of the finished board
PVC (rigid) #	Plastic	1.42	1420	88.65	0.0513	Chlorinated, hence denser than the polyolefins
Acrylic (PMMA) #	Plastic	1.19	1190	74.29	0.04299	Clear, dense for a commodity plastic
Polycarbonate #	Plastic	1.2	1200	74.91	0.04335	Transparent and tough
Nylon 6/6 #	Plastic	1.14	1140	71.17	0.04119	One of the few engineering plastics lighter than water
Acetal (POM) #	Plastic	1.41	1410	88.02	0.05094	Hard, stiff, dimensionally stable
PTFE #	Plastic	2.16	2160	134.8	0.07803	Dense for a plastic, because of the fluorine
PEEK #	Plastic	1.3	1300	81.16	0.04697	Unfilled high-temperature engineering plastic
UHMW-PE #	Plastic	0.94	940	58.68	0.03396	Floats; lightest common engineering plastic
HDPE #	Plastic	0.95	950	59.31	0.03432	Floats; used for pipe and tanks
Polypropylene #	Plastic	0.905	905	56.5	0.0327	Lightest of the commodity plastics
Balsa #	Wood	0.16	160	9.988	0.00578	Lightest commercial timber
Pine (softwood) #	Wood	0.51	510	31.84	0.01842	At 12% moisture content
Oak (hardwood) #	Wood	0.7	700	43.7	0.02529	At 12% moisture content
Rubber (natural) #	Elastomer	0.92	920	57.43	0.03324	Unfilled gum rubber
Ice #	Other	0.917	917	57.25	0.03313	Less dense than water — which is why it floats

Densities are typical published values at room temperature. Alloys within a family spread widely — aluminium alloys run 2.64 to 2.83 g/cm³ and stainless steels 7.7 to 8.1 — so use the specific alloy's figure for weight-critical work, not the family average. Gas densities are at 20 °C and 1 atm; gases are compressible, so their density changes with pressure and temperature in a way solids and liquids do not. Values for sand, cement, brick and gypsum board are bulk densities including voids, which is why they are much lower than the density of the solid material.

Density, Specific Gravity and Specific Weight

Three related quantities get used interchangeably in conversation and are not the same thing.

Density is mass per unit volume — 7 850 kg/m³ for steel. It is an absolute quantity with units. Specific gravity (relative density) is the ratio of a material's density to water's, so it is dimensionless: steel's is 7.85. The convenience is that specific gravity in g/cm³ and density in g/cm³ have the same numeric value, because water is 1 g/cm³ by definition — which is why the two columns look identical in metric.

Specific weight is weight per unit volume, so it includes gravity: steel's is about 77 kN/m³ or 490 lb/ft³. Confusing density with specific weight is the classic error, and it produces a factor-of-9.81 mistake in SI and a factor-of-32.2 mistake in imperial units. If a calculation comes out roughly ten times too large or too small, this is usually why.

For weight calculations from this table, one shortcut is worth remembering: in metric, kg/m³ ÷ 1 000 gives g/cm³, and a material at 7.85 g/cm³ weighs 7.85 kg per square metre per millimetre of thickness. That single relationship covers most plate, sheet and bar weight estimates.

Why Alloy and Temperature Matter

The table gives one number per material, and real parts vary around it. Three sources of variation are worth knowing.

Alloying. Adding heavier elements raises density and lighter ones lowers it. Aluminium at 2.70 g/cm³ becomes 2.81 in 7075 because of its zinc and copper content, and stainless steel at 7.90 becomes 8.00 in grade 316 because of the molybdenum. Within a family the spread is typically ±3%, which matters for a weight take-off and not for a strength calculation.

Temperature. Solids and liquids expand when heated, so their density falls. Water is the awkward exception in the range that matters: it reaches maximum density at 4 °C, which is why ice floats and why the 4 °C figure — not the 20 °C figure — is the one tied to the definition of the litre. For metals the change is small, roughly 0.5% over 100 °C.

Porosity and bulk condition. This is the largest effect and applies to the building materials in the table. Sand at 1.60 g/cm³ and cement at 1.44 are bulk densities — they include the air between particles. The solid mineral itself is around 2.65. If you are calculating the weight of a hopper or a truck load, use the bulk density; if you are calculating what the material is made of, use the solid density.

Frequently Asked Questions

What is the density of steel?: 7.85 g/cm³, which is 7 850 kg/m³ or 490 lb/ft³. This is the standard figure for carbon and low-alloy steel and is what this site uses for every steel weight calculation. Stainless steel is slightly denser at 7.9 to 8.0 g/cm³ depending on grade, so a stainless part weighs about 1% more than the same part in carbon steel.
How do I convert density to weight?: Multiply density by volume. In metric, kg/m³ × m³ gives kilograms directly — a 2 m × 1 m plate of 10 mm steel is 0.02 m³, and 0.02 × 7 850 = 157 kg. In imperial, lb/ft³ × ft³ gives pounds. Watch the units: density in kg/m³ with volume in cm³ gives an answer a million times too large. The relationship kg/m² = 7.85 × thickness in mm for steel is the shortcut worth memorising.
Why does ice float on water?: Because ice is less dense than liquid water — 0.917 g/cm³ against 1.000 at 4 °C. Most substances are denser as solids than as liquids, but water's hydrogen bonding holds the molecules further apart in the crystal lattice than in the liquid, so freezing expands it by about 9% in volume. This is why water pipes burst when they freeze, and why the 4 °C figure is the point of maximum density.
What is the densest material in the chart?: Tungsten at 19.25 g/cm³ among the engineering metals, and mercury at 13.534 among the liquids. Tungsten's density is why it is used for radiation shielding, counterweights and kinetic penetrators. Lead at 11.34 is the cheaper and more easily worked alternative where the extra density is not essential.
Is specific gravity the same as density?: No — specific gravity is dimensionless and density has units. Specific gravity is the ratio of a material's density to water's, so steel's is 7.85. In the metric system the numbers coincide (7.85 g/cm³ and a specific gravity of 7.85) because water is 1 g/cm³, which is why the two get used interchangeably and why that habit causes errors when working in lb/ft³.

Value Sources

Each data column on this page is tied to the source it came from. The numbers in square brackets correspond to the table headers above.

#	Source	Type	Revision / method
[1]	Published density values for engineering materials (handbook compilations)	standard	compilations as published 2024–2026
[2]	Density converted from g/cm³ to kg/m³	derived	kg/m³ = g/cm³ × 1000 exactly. Checked at build time against every row to within 0.2%.
[3]	Density converted to lb/ft³ and lb/in³	derived	lb/ft³ = kg/m³ × 0.0624279606 and lb/in³ = g/cm³ × 0.0361273, both exact conversions. Checked at build time against every row.

Data Sources

Standard	Revision	What it covers on this page
Density of water at 4 °C — 1 000 kg/m³	n/a — defining value of the metric system, not a revisioned document	the reference point for specific gravity
Published handbook densities for engineering materials	compilations as published 2024–2026	every value in the table
ASTM D792 — Density and Specific Gravity of Plastics by Displacement	ASTM D792-20	the method behind the polymer densities

Cross-checked against:

Metal densities checked against the values published on this site's own material data sheets
Polymer densities checked against the plastics property pages, which cite supplier data sheets
Every unit conversion recomputed at build time and compared against the printed value
Key reference values held as known-value checks — water, steel, aluminium, copper, mercury

Derived values — the following values on this page are calculated, not taken directly from the standard:

Value	How it is derived
Density in kg/m³	g/cm³ × 1000. Rechecked at build time for every row to within 0.2%.
Density in lb/ft³ and lb/in³	Exact conversions from the metric figures — kg/m³ × 0.0624279606 and g/cm³ × 0.0361273. Rechecked at build time for every row.

Values are typical for the material class at room temperature. Alloys within a family vary by roughly ±3%, gases vary strongly with pressure and temperature, and bulk densities of sand, cement and similar materials depend on how they are packed. Use the specific material's certified density for weight-critical work.

Accuracy and use. The values on this page are compiled from the published standards and cross-checked sources listed above. Where values are derived, the derivation is stated. No warranty, express or implied, is made as to the accuracy or completeness of this information, and no liability is accepted for any loss or damage arising from its use. Engineering reference data is provided for guidance in preliminary work — before a value is used for design, fabrication or acceptance testing, verify it against the current revision of the governing standard and against your own inspection. The user assumes all risk and responsibility in connection with the use of this information.

Cite This Page

Every value on this page is traceable to the sources listed above. If you use the data in a document, paper or report, cite it as:

Plain text

Engineering Reference. "Density Chart." https://refmanual.com/charts/density-chart/ (accessed 2026-09-29). Data from Density of water at 4 °C — 1 000 kg/m³, n/a — defining value of the metric system, not a revisioned document.

BibTeX

@misc{density-chart,
  title        = {Density Chart},
  author       = {{Engineering Reference}},
  howpublished = {\url{https://refmanual.com/charts/density-chart/}},
  note         = {Accessed: 2026-09-29},
  source       = {Density of water at 4 °C — 1 000 kg/m³, n/a — defining value of the metric system, not a revisioned document}
}

RIS (EndNote, Zotero, Mendeley)

TY  - ELEC
TI  - Density Chart
AU  - Engineering Reference
PB  - Engineering Reference
UR  - https://refmanual.com/charts/density-chart/
PY  - 2026
DA  - 2026-09-29
N1  - Source: Density of water at 4 °C — 1 000 kg/m³, n/a — defining value of the metric system, not a revisioned document
ER  -

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