🖥️ PCB Trace Width Calculator
Based on IPC-2221 standard. Calculate minimum trace width to carry a given current with an acceptable temperature rise.
Layer Type
External traces have better heat dissipation (k = 0.048). Internal traces run hotter (k = 0.024).
Parameters
IPC-2221: W = A / (Tcu × 1.378) | A = [I / (k × ΔT⁰·⁴⁴)]^(1/0.725)
°C
°C
⚠ Please enter a valid current value.
Results
Quick Reference — Copper Weights
| Copper Weight | Thickness (µm) | Thickness (mils) | Typical Use |
|---|---|---|---|
| 0.5 oz/ft² | 17.5 µm | 0.69 mil | Fine-pitch signal traces |
| 1 oz/ft² | 35 µm | 1.37 mil | Standard — most boards |
| 2 oz/ft² | 70 µm | 2.74 mil | Power traces, high current |
| 3 oz/ft² | 105 µm | 4.11 mil | High-power applications |
| 4 oz/ft² | 140 µm | 5.48 mil | Heavy power / bus bars |
⚠ IPC-2221 is conservative and based on empirical data from older boards. Real-world capacity may be higher, especially with pours, vias, or heatsinking. Always add margin for safety-critical applications and verify with your PCB manufacturer's capabilities.
Current vs. Width Reference (1 oz, ΔT = 10 °C)
| Current (A) | External Width (mm) | External Width (mils) | Internal Width (mm) | Internal Width (mils) |
|---|