calc.engineer / PCB & Electronics / PCB Via Current

PCB Via Current v1.0.0

Calculate PCB via current-carrying capacity using the IPC-2221 standard. A plated via is a hollow copper cylinder whose cross-sectional area is the annular ring of plating: A = pi * (D - t) * t, where D is the drill diameter and t is plating thickness. The IPC-2221 empirical formula I = k * dT^0.44 * A^0.725 (k=0.048) then gives the maximum current for a given temperature rise. Also computes via barrel resistance from copper resistivity (1.724e-6 ohm-cm) and barrel length (board thickness). When a target current is specified, returns how many parallel vias are needed. Essential for power planes, high-current paths, and thermal via arrays. Chain with trace_width to verify both trace and via can handle the same current.

← from trace_width.target_current_a← from ohms_law.target_current_afeeds trace_width →
Via drill hole diameter in millimeters. Common values: 0.2 (microvia), 0.3 (standard), 0.4, 0.6, 0.8, 1.0.
Copper plating thickness on the via barrel wall in micrometers. Standard is 25 um (IPC Class 2). Heavy plating is 50 um (IPC Class 3).
Total PCB board thickness in millimeters. Standard 2-layer is 1.6 mm. Common values: 0.8, 1.0, 1.6, 2.0, 2.4.
Allowable temperature rise above ambient in degrees Celsius. IPC-2221 standard uses 10, 20, or 30 C.
Optional target current in amperes. When provided, calculates how many parallel vias are needed to carry this current safely.
Fill in the inputs and Compute to see the structured result.

From an agent (MCP) or the API

curl -X POST https://calc.engineer/api/pcb_via_current \
  -H "Content-Type: application/json" \
  -d '{"drill_diameter_mm": …, "plating_thickness_um": …, "board_thickness_mm": …}'

MCP: connect to https://calc.engineer/mcp and call pcb_via_current.

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