PCB Trace Width Calculator

Current (I)

Temperature rise (ΔT)

ΔT = how much hotter the trace is allowed to be above ambient

Ambient temperature

Copper thickness

Common: 1 oz ≈ 1.37 mil ≈ 35 µm

Trace length

Length used for R = ρ·L/A (L in meters)

Internal layers

Required width (W)

Resistance (Ω) Voltage drop (V) Power loss (W)

External layers (in air)

Required width (W)

Resistance (Ω) Voltage drop (V) Power loss (W)

Operating trace temperature

Operating temp = ambient + ΔT (shown in °C and °F)

Formula (IPC-2221 style)

Step-1 (Cross-sectional Area)

\[ A = \left( \frac{I}{k \times (\Delta T)^b} \right)^{\tfrac{1}{c}} \]

Step-2 (Trace Width)

\[ W_{\text{mil}} = \frac{A \; (mil^2)}{\text{thickness (mil)}} \]

Constants

Internal layers: \( k = 0.024,\; b = 0.44,\; c = 0.725 \)
External (in air): \( k = 0.048,\; b = 0.44,\; c = 0.725 \)

Notes:
- \(A\) is computed in square-mils (mil²).
- Thickness is converted to mils.
- Final width \(W\) is displayed in the unit chosen (mil, mm, or µm).

PCB Trace Width Calculator

Internal layers

External layers (in air)

Formula (IPC-2221 style)

Quick Information

Information

Customer Service