PCB Trace Width Calculator
When high current flows through a PCB trace, it generates heat. To prevent delamination or burning, the trace must be wide enough to dissipate that heat.
This calculator uses the IPC-2221 Standard to determine the minimum required trace width for a given current and allowable temperature rise. It also checks for Voltage Drop and Power Loss.
Design Parameters
InputThermal Limits
IPC-2221Required Geometry
ResultElectrical Characteristics
IPC-2221 Formulas Explained
Required Area
Area = (I / (k × ΔT0.44))(1/0.725)
k = 0.048 (External) or 0.024 (Internal). Result in mils².Trace Width
Width = Area / (Thickness × 1.378)
Thickness in oz/ft². 1 oz copper ≈ 1.378 mils thick.Resistance
R = (ρ × L) / (W × T)
ρ (Copper Resistivity) ≈ 1.7e-6 Ω-cm at room temp.Power Loss
P = I2 × R
Energy dissipated as heat along the trace length.How to Use
Calculate PCB trace widths in 3 steps.
Define Electrical Load
Enter the maximum Current your trace needs to carry. Select the Copper Weight (usually 1 oz) and whether it’s an External or Internal layer.
Set Thermal Constraints
Specify the allowed Temperature Rise (e.g., 10°C means the trace can heat up to 35°C if ambient is 25°C). Higher rise allows thinner traces.
Get Trace Dimensions
The tool calculates the minimum Trace Width in mils and mm. It also provides the DC Resistance and Voltage Drop for the specified length.