Calculate minimum PCB trace width for current carrying capacity using IPC-2221.
| Current | External | Internal |
|---|---|---|
| 0.5 A | 6 mil | 12 mil |
| 1.0 A | 10 mil | 20 mil |
| 2.0 A | 20 mil | 39 mil |
| 3.0 A | 30 mil | 58 mil |
| 5.0 A | 48 mil | 95 mil |
This calculator uses the IPC-2221 standard formula to determine minimum trace width based on:
For most applications, 10°C is a safe choice. Higher values (20-30°C) can be used where board temperature is less critical, but stay under 45°C for reliability.
Internal traces are surrounded by FR4 dielectric which is a poor thermal conductor. External traces can dissipate heat to air more efficiently, allowing them to be narrower for the same current.
This calculator focuses on thermal limits. For power distribution, also verify voltage drop is acceptable using our Voltage Drop Calculator.