Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

Allowed rise (°C)

Required number input.

Via barrel length (m)

Required number input.

Inner barrel radius (m)

Required number input.

Copper plating thickness (m)

Required number input.

Copper resistivity (Ω·m)

Required number input.

Effective thermal resistance (°C/W)

Required number input.

Estimate via current from an allowed temperature rise and user-supplied effective thermal resistance using I=sqrt(ΔT/(R_electrical·R_thermal)). Barrel electrical resistance uses copper resistivity, length, and plated annulus area. This simplified lumped model requires board-specific thermal resistance. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Electrical Resistance ohm

The resulting electrical resistance ohm returned as a number.

Estimated Current A

The resulting estimated current a returned as a number.

• PCB trace calculations depend on finished copper thickness, geometry, dielectric stack-up, temperature rise criterion, ambient, neighboring conductors, return path, frequency, surface finish, and fabrication tolerance. IPC equations are approximations, not a substitute for the board fabricator's stack-up or field solving.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

• IPC-2221 PCB Trace Current Estimate

  Estimate PCB trace current with the legacy IPC-2221 empirical equation I=k·ΔT^0.44·A^0.725, with A in square mils and k=0.048 external or 0.024 internal. This is a rough thermal estimate; modern IPC-2152 data and board-specific validation are preferable for design sign-off.

• Thermal Via Barrel Resistance

  Estimate one-dimensional thermal resistance through the plated via barrel, L/(kA), where A is the annular copper cross-section. Board laminate, pads, and spreading resistance are excluded.

• Copper Loss

  Compute resistive winding or conductor loss as I²R from RMS current and resistance at the relevant operating temperature. Output is watts; AC skin and proximity effects are not included unless already reflected in the supplied resistance.