Density of Copper: 8,960 kg/m³ — Alloys, Wire Weight, and Engineering Use
Pure copper has a density of 8,960 kg/m³ (8.96 g/cm³) and is the most important industrial conductor metal. Its high density sits alongside excellent electrical and thermal conductivity, making it central to electrical engineering.
Copper alloys such as brass, bronze, and beryllium copper vary from 7,500–8,900 kg/m³ depending on composition. This page gives pure copper and alloy density values, copper wire weight estimation methods, and conductor comparisons, with live calculations available in the material density calculator.
Key values
Copper Density: Key Values
kg/m³
8,960 kg/m³
Pure copper (Cu) at 20°C
g/cm³
8.96 g/cm³
Standard reference value
lb/ft³
559.4 lb/ft³
U.S. engineering reference
Values are for commercially pure copper (C10100 / C11000 series, 99.9%+ Cu) at 20°C.
Copper melts at 1,085°C; liquid copper density is approximately 8,000 kg/m³.
IEC and ASTM standards use 8,890 kg/m³ as the reference for annealed copper conductors in electrical calculations.
Alloys
Copper Alloy Density Chart
Pure copper has relatively low strength, so engineering applications often add zinc, tin, aluminum, beryllium, or other elements to improve strength, wear resistance, or corrosion resistance. Alloying usually lowers density, but the amount depends on the alloy system.
| Alloy | Common Name | Key Elements | Density | Typical Use |
|---|---|---|---|---|
| C10100 / C11000 | Electrolytic tough pitch copper | 99.9%+ Cu | 8,960 kg/m³ | Electrical wire, busbars |
| C17200 | Beryllium copper | Cu + 1.9% Be | 8,250 kg/m³ | Springs, connectors, non-sparking tools |
| C22000 | Commercial bronze | Cu + 10% Zn | 8,800 kg/m³ | Architectural, hardware |
| C26000 | Cartridge brass | Cu + 30% Zn | 8,530 kg/m³ | Ammunition, fasteners |
| C36000 | Free-cutting brass | Cu + 35% Zn + 3% Pb | 8,490 kg/m³ | Machined fittings, valves |
| C46400 | Naval brass | Cu + 39% Zn + 1% Sn | 8,410 kg/m³ | Marine hardware |
| C51000 | Phosphor bronze | Cu + 5% Sn + 0.2% P | 8,860 kg/m³ | Springs, bearings, bushings |
| C63000 | Aluminum bronze | Cu + 10% Al + 5% Ni | 7,580 kg/m³ | Marine, aerospace fittings |
| C93200 | Bearing bronze | Cu + 7% Sn + 7% Pb | 8,930 kg/m³ | Bushings, bearings |
| Cupronickel 90/10 | Cupronickel | Cu + 10% Ni | 8,900 kg/m³ | Marine piping, coins |
| Cupronickel 70/30 | Cupronickel | Cu + 30% Ni | 8,950 kg/m³ | Heat exchangers, condenser tubes |
Brass (copper-zinc alloys) density decreases as zinc content increases, because zinc (7,133 kg/m³) is less dense than copper (8,960 kg/m³). Bronze (copper-tin alloys) density stays closer to pure copper because tin (7,265 kg/m³) has a similar density to zinc but is used in smaller proportions.
For broader alloy and material comparisons, open the density table.
Conductors
Density of Copper vs Other Electrical Conductors
Copper is the most widely used electrical conductor, but in some applications it competes with aluminum, silver, or gold. Density differences directly affect conductor weight and cost, making density a key parameter in electrical engineering material selection.
| Conductor | Density (kg/m³) | Conductivity (% IACS) | Density × Cost factor | Notes |
|---|---|---|---|---|
| Silver | 10,490 | 106% | Very high | Best conductor, cost-prohibitive |
| Copper (annealed) | 8,960 | 100% | Medium-high | Industry standard |
| Gold | 19,320 | 71% | Extremely high | Contact plating only; see density of gold |
| Aluminum | 2,700 | 61% | Low | Overhead power lines, weight-sensitive; see density of aluminum |
| Tungsten | 19,250 | 31% | High | High-temperature filaments |
| Nickel | 8,908 | 25% | Medium | Corrosion-resistant applications |
| Iron / Steel | 7,874 | 17% | Low | Grounding, non-critical conductors |
Aluminum's conductivity is 61% of copper's, but its density is only 30% of copper's. For overhead power transmission lines where weight matters more than conductor cross-section, aluminum (often reinforced with a steel core — ACSR) is preferred despite its lower conductivity.
Wire weight
Copper Wire Weight Estimation
Copper wire weight calculation is a common need in electrical engineering procurement and construction. If conductor cross-sectional area and length are known, weight can be calculated directly from density.
Formula
m = ρ × A × L
- m = mass (kg)
- ρ = copper density = 8,960 kg/m³ (or 8.96 g/cm³)
- A = cross-sectional area (m²)
- L = length (m)
Unit check
Convert wire area from mm² to m² before multiplying. For example, 2.5 mm² = 2.5 × 10⁻⁶ m². When density is in kg/m³, area is in m², and length is in m, the result is kilograms.
Example 1 — Standard electrical wire (2.5 mm² conductor)
Cross-section: 2.5 mm² = 2.5 × 10⁻⁶ m²
Length: 100 m
Mass = 8,960 × 2.5 × 10⁻⁶ × 100 = 2.24 kg per 100 m
Industry reference: 2.5 mm² copper wire weighs approximately 22.4 kg/km
Example 2 — Power cable (95 mm² conductor)
Cross-section: 95 mm² = 95 × 10⁻⁶ m²
Length: 500 m
Mass = 8,960 × 95 × 10⁻⁶ × 500 = 425.6 kg
Example 3 — Copper busbar
A rectangular busbar 50 mm × 6 mm × 2 m long:
Volume = 0.05 × 0.006 × 2 = 6 × 10⁻⁴ m³
Mass = 8,960 × 6 × 10⁻⁴ = 5.38 kg
Example 4 — Copper vs aluminum wire comparison
Same 95 mm² conductor, 500 m, in aluminum (2,700 kg/m³):
Mass = 2,700 × 95 × 10⁻⁶ × 500 = 128.3 kg
Copper version is 3.3× heavier than aluminum at equal cross-section.
To match copper's conductivity, aluminum needs ~1.64× larger cross-section, giving 156 mm² aluminum at 210 kg — still 50% lighter than copper.
Atomic structure
Why Is Copper So Dense?
Atomic mass: Copper's atomic mass is 63.5 atomic mass units (u), placing it among the heavier transition metals. For comparison, aluminum is 27 u and iron is 56 u. Heavier atoms, packed at similar densities, produce a denser material — this is the primary reason copper is denser than aluminum by a factor of 3.3. For the base mass-per-volume concept, see what is density.
Crystal structure: Copper adopts a face-centered cubic (FCC) crystal structure, the same as gold and aluminum. FCC packing achieves a theoretical packing efficiency of 74%, meaning 74% of the volume is occupied by atoms and 26% is empty space. The high packing efficiency combined with copper's relatively heavy atoms produces its characteristic density of 8,960 kg/m³.
Density and conductivity: Copper's density is directly linked to its electronic structure. The single free electron per copper atom that makes it an excellent conductor also contributes to its metallic bonding strength and compact atomic arrangement. This is why the metals with the highest conductivity — silver, copper, gold — all have relatively high densities compared to structural metals like aluminum.
Calculate Copper Mass or Volume
Material Density Calculator
Select copper or any alloy and solve for mass, volume, or density. Supports custom density input for specific copper alloy grades.
Density of Aluminum
Compare copper against aluminum for electrical and structural applications — density, conductivity, and weight trade-offs explained.
FAQ
Frequently Asked Questions
What is the density of copper in kg/m³?
Pure copper has a density of 8,960 kg/m³ at 20°C. For electrical engineering calculations, IEC and ASTM standards use 8,890 kg/m³ as the reference value for annealed copper conductors. Copper alloys such as brass and bronze range from about 7,500 to 8,960 kg/m³ depending on composition.
What is the density of copper in g/cm³?
The density of copper is 8.96 g/cm³. This is the value most commonly cited in chemistry and materials science references. For comparison, aluminum is 2.70 g/cm³ (about 3× less dense) and gold is 19.32 g/cm³ (about 2.2× denser).
What is the density of brass?
Brass density depends on the zinc content. Common brass alloys range from about 8,490 to 8,800 kg/m³. Cartridge brass (70% Cu, 30% Zn) is approximately 8,530 kg/m³. As zinc content increases, density decreases because zinc (7,133 kg/m³) is less dense than copper (8,960 kg/m³).
What is the density of bronze?
Bronze density varies by alloy type. Phosphor bronze (95% Cu, 5% Sn) is approximately 8,860 kg/m³, close to pure copper. Aluminum bronze (Cu + 10% Al) is significantly lighter at about 7,580 kg/m³ because aluminum is much less dense than copper. Bearing bronze (Cu + 7% Sn + 7% Pb) is about 8,930 kg/m³.
How do I calculate the weight of copper wire?
Multiply the cross-sectional area (in m²) by the length (in m) by copper's density (8,960 kg/m³). For example, 100 m of 2.5 mm² copper wire: mass = 8,960 × 2.5×10⁻⁶ × 100 = 2.24 kg. The material density calculator above can perform this calculation automatically.
Is copper heavier than steel?
Yes. Copper (8,960 kg/m³) is denser than carbon steel (7,850 kg/m³) by about 14%. However, copper is much softer and more expensive than steel, so it is not used as a structural material. Copper's value lies in its electrical and thermal conductivity, not its mechanical properties. See density of steel for the steel reference value.