How thick is 1 ounce of copper on a PCB?
18 February 2025
Views: 2202
When manufacturing PCBs, you may often hear the description "1 ounce of copper", which refers to the thickness of copper used in PCBs. So what does "1 ounce of copper" mean and how thick is it?
Understanding "1 ounce of copper"
The term "1 ounce of copper" is a standard unit of measurement in the PCB industry, referring to the amount of copper (by weight) that can cover 1 square foot of a circuit board. 1 ounce of copper means 1 ounce of copper is evenly distributed over 1 square foot of PCB area.
Convert 1 ounce of copper to millimeters
The known density of copper is 8.96 g/cm³. Using this density, we can calculate the thickness of 1 ounce of copper on a PCB. The thickness was determined to be 0.0318 mm, or about 31.8 microns.
Copper Thickness of Different Ounces
The thickness of copper on a PCB varies depending on the design requirements. The following are common copper weights and their corresponding thickness references:
| Copper Weight (oz) |
Thickness (mm) |
Thickness (µm) |
| 0.5 oz |
0.0159 mm |
15.9 µm |
| 1 oz |
0.0318 mm |
31.8 µm |
| 2 oz |
0.0635 mm |
63.5 µm |
| 3 oz |
0.0953 mm |
95.3 µm |
| 4 oz |
0.127 mm |
127 µm |
Why copper thickness is important
Copper thickness can affect the PCB current carrying capacity, heat dissipation, PCB robustness, signal, etc. For applications that require higher current and better heat dissipation, designers will choose thicker 2 ounce or 3 ounce copper layers.
Conclusion
The thickness of 1 ounce copper on a PCB is 0.0318 mm (31.8 microns). Choosing the right copper thickness is an indispensable step in PCB design.
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