🕳️ Via Current Calculator
Calculate current capacity, resistance, and inductance of a PCB via barrel. Based on IPC-2221.
Layer Type
External vias have better heat dissipation (k = 0.048). Internal vias run hotter (k = 0.024).
$$A = \pi\,d\,t \qquad I = k\,\Delta T^{0.44}\,A^{0.725}$$
A is the barrel cross-section area in mil² (circumference × plating thickness). k = 0.048 external, 0.024 internal.
Typical: 0.025 mm (1 mil) per IPC class 2
Typical: 10 °C (conservative), 20–40 °C acceptable
⚠ Please enter drill diameter, plating thickness, and board thickness.
Results
Notes
The IPC-2221 formula gives a conservative estimate of current-carrying capacity based on the via barrel cross-section area. Real-world capacity may be higher depending on board copper pour, thermal vias, and airflow. The resistance formula uses copper resistivity ρ = 1.724 × 10⁻⁸ Ω·m. Via inductance is estimated from the Wheeler approximation: L ≈ (µ₀ h / 2π) × ln(4h/d).