PCB Via Current Calculator
Calculate via current capacity and thermal characteristics
Input Parameters
Finished hole diameter
Copper barrel plating
PCB thickness for through-hole vias
Allowable temp rise above ambient
Required current to carry (for via count calculation)
Calculated Results
Single Via Current Capacity
Vias Needed for 1A
Single Via Resistance
1.171 mΩ
Parallel Resistance
1.171 mΩ
Voltage Drop @ 1A
1.17 mV
Standard Via Sizes
Design Tips
- Use thermal vias under hot components
- Via-in-pad requires filled and planarized vias
- Add 20% safety margin for current ratings
- Consider aspect ratio limits (depth/diameter)
Understanding PCB Via Current Capacity
What Determines Via Current Capacity?
A via's current carrying capacity depends on the cross-sectional area of copper in the barrel plating, the via length, and the allowable temperature rise. The plating thickness is typically 18-35µm depending on IPC class requirements.
Using Multiple Vias
For high-current applications, use multiple vias in parallel. This reduces both electrical resistance and thermal impedance. A common rule of thumb is to use 0.5A per standard via for conservative designs.
Thermal Vias
Thermal vias connect component pads to internal copper planes for heat dissipation. They should be filled or capped for SMD applications. A grid of thermal vias under a hot component can significantly reduce junction temperature.