Convert between copper weight (oz/ft²) and thickness in mils, micrometers, and millimeters. Essential for PCB stackup design, trace width calculations, and impedance modeling.
Conversion factor: 1 oz/ft² = 1.4 mil = 35.56 µm = 0.03556 mm
| Copper Weight (oz/ft²) | Thickness (mil) | Thickness (µm) | Thickness (mm) | Typical Use |
|---|---|---|---|---|
| 0.5 oz | 0.7 | 17.5 | 0.0175 | Fine-pitch HDI inner layers |
| 1 oz | 1.4 | 35 | 0.035 | Standard PCB (most common) |
| 2 oz | 2.8 | 70 | 0.070 | Power electronics, LED boards |
| 3 oz | 4.2 | 105 | 0.105 | High-current industrial |
| 4 oz | 5.6 | 140 | 0.140 | Automotive, heavy copper |
| 6 oz | 8.4 | 210 | 0.210 | Bus bars, extreme current |
Copper weight is expressed in ounces per square foot (oz/ft²). One ounce of copper spread uniformly over one square foot produces a foil 1.4 mils (35 µm) thick. This convention dates back to the early days of PCB manufacturing and remains the industry standard.
Copper thickness directly affects trace current capacity, impedance, and thermal performance. Thicker copper carries more current at the same trace width but costs more and limits minimum trace/space for etching. Most standard PCBs use 1 oz copper; power boards use 2–4 oz.