The melting point of copper is 1,085°C (1,985°F, or 1,358 K). This is one of the most precisely measured values in materials science — copper is a pure element, so it melts at a single exact temperature rather than over a range, and that temperature has been confirmed by multiple independent measurement methods to within 0.5°C.
This single number places copper in a specific position among structural and fabrication metals: far above the melting point of aluminum (660°C), well above the melting point of common brass (885–955°C depending on grade), and substantially below the melting point of carbon steel (1,425–1,540°C) and stainless steel (1,400–1,455°C). Understanding where copper sits on this scale — and why it sits there — is the foundation for every high-temperature process that involves copper: casting, brazing, annealing, and laser cutting.
The Melting Point of Copper in Every Unit System
Copper’s melting point expressed across all common unit systems, derived from the NIST Standard Reference Database value of 1,084.62°C:
| Unit system | Value | Application |
|---|---|---|
| Celsius (°C) | 1,084.62 | SI standard; scientific and engineering reference |
| Fahrenheit (°F) | 1,984.32 | US customary; fabrication and foundry practice |
| Kelvin (K) | 1,357.77 | Thermodynamic calculations; scientific reference |
| Rankine (°R) | 2,443.99 | US engineering thermodynamics |
In practice, these values are rounded to 1,085°C / 1,985°F / 1,358 K for engineering use. The full precision value (1,084.62°C) is relevant in calibration work, thermocouple verification, and reference material certification — copper wire and rods are used as fixed-point calibration standards for thermocouples precisely because the melting point is so sharply defined and reproducible.
Unit conversion formulas:
- °C to °F: °F = (°C × 9/5) + 32 → (1,084.62 × 1.8) + 32 = 1,984.32°F
- °C to K: K = °C + 273.15 → 1,084.62 + 273.15 = 1,357.77 K
- °F to °C: °C = (°F − 32) × 5/9 → (1,985 − 32) × 0.5556 = 1,085°C ✓
Why Copper Melts at a Single Point — The Pure Element Difference
The melting point of copper is a single temperature, not a range. This is a fundamental property of pure elements: at exactly 1,085°C and standard atmospheric pressure, copper undergoes a sharp first-order phase transition from solid face-centered cubic (FCC) crystal to liquid.
The FCC crystal structure and metallic bonding
At room temperature, copper atoms arrange in a face-centered cubic lattice — the same crystal structure as aluminum, nickel, and gold. In FCC packing, each copper atom has 12 nearest neighbors, giving a packing efficiency of approximately 74%. This efficient packing is part of why copper is denser than many metals with higher atomic numbers: the atoms pack closely and the metallic bonds are strong.
Copper’s metallic bonding arises from the delocalization of its outermost electrons (the single 4s electron, plus partial contribution from the filled 3d subshell) into a conduction band shared across the crystal. This electron sea model explains copper’s high electrical conductivity, high thermal conductivity, and characteristic reddish color — the 3d electrons participate in selective absorption of light in the blue-violet range, leaving the red-orange reflected.
Why 1,085°C specifically
The melting temperature is determined by the energy required to overcome the metallic bond forces and achieve the disordered, higher-entropy liquid state. Copper’s 3d subshell is filled (electron configuration [Ar] 3d¹⁰ 4s¹), which means the 3d electrons are more tightly bound than in transition metals with partially filled 3d shells. This produces a relatively strong metallic bond for a single-valence metal.
Compared to its neighbors in the periodic table:
- Nickel (Z=28, [Ar] 3d⁸ 4s²): melts at 1,455°C — higher, because two valence electrons and a half-filled 3d subshell contribute to stronger bonding
- Zinc (Z=30, [Ar] 3d¹⁰ 4s²): melts at 419°C — much lower, despite a filled 3d shell, because the larger atomic radius weakens the metallic bond
- Silver (Z=47, [Kr] 4d¹⁰ 5s¹): melts at 962°C — lower than copper, because the larger atom size weakens bonding despite a similar electron configuration
- Gold (Z=79, [Xe] 4f¹⁴ 5d¹⁰ 6s¹): melts at 1,064°C — slightly below copper, with relativistic effects contracting the 6s orbital and strengthening Au-Au bonding relative to expectations from atomic radius alone
Copper’s 1,085°C melting point is therefore exactly what its electronic structure and atomic radius predict: a moderately strong metallic bond, a tightly packed FCC lattice, and a melting temperature in the upper-middle range for common non-ferrous metals.
Melting Point of Copper vs. Other Engineering Metals
For fabricators making material selections, this comparison table is the most useful form of the copper melting point data:
| Metal | Melting point (°C) | Melting point (°F) | Ratio to copper |
|---|---|---|---|
| Aluminum (pure) | 660 | 1,220 | 0.61× |
| Aluminum 6061 alloy | 582–652 | 1,080–1,206 | — |
| Zinc (pure) | 419 | 786 | 0.39× |
| Lead (pure) | 327 | 621 | 0.30× |
| Yellow brass (C27000) | 905–932 | 1,661–1,710 | 0.83–0.86× |
| Red brass (C23000) | 990–1,025 | 1,814–1,877 | 0.91–0.94× |
| Silver (pure) | 962 | 1,764 | 0.89× |
| Gold (pure) | 1,064 | 1,947 | 0.98× |
| Copper (pure) | 1,085 | 1,985 | 1.00× |
| Carbon steel (A36) | 1,425–1,540 | 2,597–2,804 | 1.31–1.42× |
| 304 stainless steel | 1,400–1,455 | 2,552–2,651 | 1.29–1.34× |
| Titanium (pure) | 1,668 | 3,034 | 1.54× |
| Tungsten (pure) | 3,422 | 6,192 | 3.16× |
Source: ASM Handbook, Volume 2; CRC Handbook of Chemistry and Physics, 104th Edition.
Three practical conclusions from this table stand out for fabrication work:
Copper melts significantly below steel. Any furnace, forge, or laser setup designed for steel operates well above copper’s melting point. Thermal management is more critical with copper than steel — the margin between annealing temperature and melting is smaller and the risk of accidental overheating is higher.
Copper melts above most of its alloying elements. Zinc (419°C) and lead (327°C) both melt far below copper. In copper alloys like brass, these lower-melting elements reduce the solidus of the alloy through solid-solution and eutectic effects, which is why all commercial brasses melt below pure copper.
Copper is close to gold and silver in melting temperature. This reflects their shared Group 11 position in the periodic table and similar FCC crystal structures. The three coinage metals melt within a 123°C band of each other (962°C to 1,085°C), which is why historical metallurgists could process all three with similar furnace and fuel technology.
The Melting Point of Copper in Fabrication Processes
Copper casting
Sand casting, investment casting, and continuous casting of copper and copper alloys require the melt to reach and exceed 1,085°C for pure copper. In practice, copper is poured at 1,120–1,200°C (2,048–2,192°F) — 35–115°C above the melting point — to ensure adequate superheat for mold fill before solidification begins.
Copper casting is complicated by its high affinity for dissolved oxygen and hydrogen at melt temperatures. Oxidizing atmospheres produce cuprous oxide (Cu₂O) inclusions; hydrogen absorbed from moisture in the furnace atmosphere or mold produces “hydrogen disease” — a porosity condition caused by steam formation during solidification. Commercial copper casting uses deoxidants (phosphorus, lithium) and controlled-atmosphere furnaces to manage gas pickup.
Copper annealing
Annealing copper to restore ductility after cold working requires temperatures of 250–650°C, depending on the degree of cold work and desired grain size — all well below the 1,085°C melting point. There is no risk of accidental melting at standard annealing temperatures. The practical thermal hazard in copper annealing is grain growth at high temperatures, not melting.
Brazing copper
Brazing joins copper components with a filler metal whose liquidus is below copper’s solidus. Since pure copper has a single melting point (not a solidus range), any filler with a liquidus below 1,085°C provides a thermal margin for base metal safety.
Common filler options for brazing copper:
- BCuP series (copper-phosphorus): liquidus 710–925°C — the standard choice for plumbing and HVAC copper; self-fluxing on copper
- BAg series (silver-based): liquidus 620–870°C — for electrical and electronic applications requiring lower process temperatures
- BCu series (pure copper filler): liquidus 1,085°C — identical to base metal; used for furnace brazing in reducing atmospheres where the thin oxide layer on the base metal prevents bonding issues
Laser cutting copper
The melting point of copper is not the primary challenge in fiber laser cutting. Pure copper’s reflectivity at 1,064 nm (the fiber laser wavelength) exceeds 95% at room temperature, meaning the laser must overcome near-total reflection before the surface absorbs enough energy to form a melt pool. Once the pool is established, the 1,085°C melting point is moderate, and the laser maintains it without difficulty.
The reflectivity challenge means that cutting copper typically requires higher power (3kW minimum for production), precise focus positioning, and often a specialized cutting strategy (reduced power ramping during piercing to avoid back-reflection damage to the laser source). High-pressure nitrogen assist is standard for clean edges. The full guide to processing copper and other reflective metals on a fiber laser is in our guide to cutting reflective metals.
Melting Point of Copper: Temperature Measurement and Calibration
The melting point of copper at 1,084.62°C is one of the defining fixed points of the International Temperature Scale of 1990 (ITS-90). This means copper’s melting and freezing point is used as a reference calibration standard for high-temperature thermometry — particularly for thermocouples operating above 900°C.
When a thermocouple is calibrated at the copper fixed point, a sample of high-purity copper (99.999%+) in a sealed graphite crucible is melted in a furnace. As it cools through the melting point, the temperature plateau produced by the latent heat of fusion is measured. The flatness and reproducibility of this plateau — typically ±0.1°C or better for properly prepared samples — is a direct measure of the copper purity and the quality of the calibration setup.
For fabricators, the practical takeaway is that thermocouple accuracy at copper-processing temperatures can be verified against a copper freeze-point cell without sending the instrument to a calibration laboratory. This is relevant for investment casting shops, heat-treating furnaces, and any operation where temperature accuracy at 1,000–1,100°C is critical.
Frequently Asked Questions About the Melting Point of Copper
Q: What is the melting point of copper in Celsius? 1,085°C (precisely 1,084.62°C per NIST Standard Reference Data). This is the temperature at which pure copper transitions from solid to liquid at standard atmospheric pressure. It is one of the ITS-90 fixed calibration points for high-temperature thermometry.
Q: What is the melting point of copper in Fahrenheit? 1,985°F (precisely 1,984.32°F). Conversion: (1,084.62 × 9/5) + 32 = 1,984.32°F.
Q: What is the melting point of copper in Kelvin? 1,358 K (precisely 1,357.77 K). Conversion: 1,084.62 + 273.15 = 1,357.77 K.
Q: Is the melting point of copper higher or lower than brass? Higher. Pure copper melts at 1,085°C; commercial brass grades melt between 885°C (Muntz metal, C28000) and 1,025°C (red brass, C23000). Brass melts below copper because the zinc alloying element (melting point 419°C) disrupts copper’s crystal lattice and lowers the energy required to initiate melting.
Q: Does the melting point of copper change with purity? Yes, but only at very high purity levels. Commercial-grade copper (99.9% pure, ASTM B152 Class C10100–C12000) melts at essentially 1,085°C for all practical purposes. At extreme purity levels (99.9999%+) used in semiconductor applications, the melting point precision improves but the value itself does not shift meaningfully. Trace impurities at commercially normal concentrations lower the melting point slightly through freezing-point depression — typically less than 1°C for 99.9% purity copper.
Q: Why is the melting point of copper important for electrical applications? Copper’s thermal properties, including its melting point, directly affect its performance in high-temperature electrical applications. Bus bars, high-current conductors, and motor windings must never approach the copper melting point in service — thermal runaway faults can bring conductor surfaces to temperatures that begin softening the copper at 700–800°C, well below melting but sufficient to cause creep, deformation, and loss of contact pressure. The melting point defines the absolute upper bound; operational temperature limits are set far below it.
References
- National Institute of Standards and Technology (NIST), NIST Standard Reference Database 69: NIST Chemistry WebBook, available at webbook.nist.gov. (Standard reference data for copper: melting point 1,084.62°C / 1,357.77 K; electron configuration [Ar] 3d¹⁰ 4s¹; ITS-90 fixed-point definition and calibration protocol.)
- ASM Handbook, Volume 2: Properties and Selection — Nonferrous Alloys and Special-Purpose Materials, 10th Edition. ASM International, Materials Park, OH, 1990. (Physical properties of copper and copper alloys: melting points, casting temperatures, annealing ranges; comparative data for brass, bronze, and copper alloy families; filler metal liquidus temperatures for copper brazing.)
- Haynes, W.M., ed., CRC Handbook of Chemistry and Physics, 104th Edition. CRC Press, Boca Raton, FL, 2024. (Elemental reference data: copper melting point, crystal structure (FCC), lattice parameter, atomic radius; comparative melting points for neighboring elements Ni, Zn, Ag, Au; physical constants used in unit conversions.)
- ASTM B152/B152M, Standard Specification for Copper Sheet, Strip, Plate, and Rolled Bar, ASTM International, current edition. (Purity classifications for commercial copper flat products C10100–C12200; the material specification governing the copper grades discussed in the casting and annealing sections.)
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