TRACE CALCULATOR

PCB Trace Width, Current Capacity & Impedance
Current → Trace Width (IPC-2221)
Required Width
IPC-2221: I = k × (ΔT^0.44) × (A^0.725)
k = 0.048 (external) / 0.024 (internal)
Trace Width → Current (IPC-2221)
mm
Max Current
IPC-2221: I = k × (ΔT^0.44) × (A^0.725)
k = 0.048 (external) / 0.024 (internal)
Current → Trace Width (IPC-2152)
Base Width (unadjusted)
Adjusted Width
Modifiers
IPC-2152: Ac = (117.555 × ΔT−0.913 + 1.15) × I(0.84 × ΔT−0.108 + 1.159)
Adjusted for board thickness, plane proximity, and layer position
Trace Width → Current (IPC-2152)
mm
Base Max Current (unadjusted)
Adjusted Max Current
Modifiers
IPC-2152: Ac = (117.555 × ΔT−0.913 + 1.15) × I(0.84 × ΔT−0.108 + 1.159)
Adjusted for board thickness, plane proximity, and layer position
Modifier values are approximations derived from IPC-2152 charts. For safety-critical designs, consult the full standard.
Microstrip Impedance (Zo)
mm
mm
Characteristic Impedance
Effective Dielectric Constant
Microstrip Formula: Zo ≈ (87/√(εr+1.41)) × ln(5.98H/(0.8W+T))
Where: W = trace width, H = dielectric thickness, T = copper thickness, εr = relative permittivity
Note: This is an approximation. For precise designs, use field solver tools.

Quick Reference: Standard Trace Widths

Width (mm) Width (mil) 1 oz @ 20°C Ext 1 oz @ 20°C Int 2 oz @ 20°C Ext 2 oz @ 20°C Int