PCB Trace Width & Current Capacity Calculator

Calculate maximum safe current carrying capacity (Amperes), trace resistance, voltage drop, and power loss for external and internal PCB layers based on IPC-2221 standards.

Layer Position

External Layer (Top / Bottom - Better Cooling) Internal Layer (Inner - Reduced Cooling)

Copper Thickness (oz / μm)

Trace Width W

1 mm ≈ 39.37 mil

Allowable Temp Rise ΔT (°C) Typical consumer PCB: 10°C–20°C; Industrial: ≤ 10°C

Trace Length (cm)

IPC-2221 Results

Max Current Capacity I_max	— A
Cross-Section Area A	— mil² (— mm²)
Trace Resistance R	— mΩ
Voltage Drop ΔV at I_max	— mV
Power Loss P_loss	— W

IPC-2221 Formulas

External: I = 0.048 × (ΔT)^0.44 × (A)^0.725

Internal: I = 0.024 × (ΔT)^0.44 × (A)^0.725

A = Trace Width (mil) × Thickness (mil)

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