PCB Trace Width Calculator
Calculate the required PCB trace width based on current, copper thickness, and maximum temperature rise.
Calculated Result
Trace Cross-section
Current vs Width Graph
Understanding PCB Trace Width Calculation
The trace width calculation is based on the IPC-2221 standard, which provides empirical formulas for determining trace width based on current carrying capacity:
Area = (I / (k × ΔT^b))^(1/c)
Width = Area / Thickness
Where:
- Area = Cross-sectional area in square mils
- I = Current in amperes
- k = 0.048 for external traces
- ΔT = Temperature rise in °C
- b = 0.44 for external traces
- c = 0.725 for external traces
Current (I)
Measured in Amperes (A)
Thickness
Measured in oz (1 oz = 1.37 mils)
Width
Calculated in mils
PCB Trace Design Guide
Key Concepts
Current Capacity
- • Based on cross-sectional area
- • Affected by copper thickness
- • Limited by temperature rise
- • Consider safety margins
Temperature Effects
- • Heat dissipation varies by layer
- • Consider board thermal design
- • Ambient temperature impact
- • Thermal relief for components
Common Applications
Power Distribution
Supply and ground planes for power delivery.
Motor Control
High-current traces for motor drivers.
LED Drivers
Current-carrying traces for LED arrays.
Design Considerations
Layer Placement
- • Inner layers have less cooling
- • Consider thermal vias
- • Use multiple layers for high current
- • Keep sensitive signals away
Safety Margins
- • Add 20-30% width margin
- • Consider peak currents
- • Account for ambient temperature
- • Plan for future upgrades