PCB Trace Resistance Calculator
Calculate resistance, voltage drop, and power dissipation of PCB traces with temperature compensation
Calculate PCB Trace Resistance
Width of the PCB trace
Length of the PCB trace
Thickness (height) of the copper trace
Operating temperature of the PCB
Material Properties
Copper: 1.68×10⁻⁸ Ω·m
Copper: 0.0039 /°C
Resistance Results
Formula: R = ρ × L / (T × W) × [1 + α × (T_amb - 25°C)]
Cross-sectional area: 0.000 mm²
Temperature factor: 1.0000
Voltage Drop Calculator
Resistance Analysis
Example Calculation
Power Supply Trace
Trace Width: 2.54 mm (100 mil)
Trace Length: 5 cm
Trace Thickness: 0.035 mm (1 oz copper)
Operating Temperature: 70°C
Current: 2 A
Results
Cross-sectional area: 0.089 mm²
Base resistance: 0.94 mΩ
Temperature factor: 1.176
Final resistance: 1.11 mΩ
Voltage drop at 2A: 2.22 mV
Power loss: 4.44 mW
Common Copper Thicknesses
Material Properties
Copper
Resistivity: 1.68×10⁻⁸ Ω·m
Temp. Coeff: 0.0039 /°C
Most common PCB material
Silver
Resistivity: 1.59×10⁻⁸ Ω·m
Temp. Coeff: 0.0038 /°C
Lower resistance than copper
Gold
Resistivity: 2.44×10⁻⁸ Ω·m
Temp. Coeff: 0.0034 /°C
Corrosion resistant
Design Tips
Wider traces reduce resistance
Shorter traces minimize voltage drop
Thicker copper reduces resistance
Consider temperature effects
Use kelvin connections for precision
Parallel traces for high current
Understanding PCB Trace Resistance
What is PCB Trace Resistance?
PCB trace resistance is the electrical resistance of copper tracks on a printed circuit board. This resistance causes voltage drops and power losses that can affect circuit performance, especially in high-current applications.
Why Calculate Trace Resistance?
- •Determine voltage drops in power distribution
- •Calculate power losses and heating effects
- •Optimize trace dimensions for performance
- •Ensure signal integrity in sensitive circuits
Resistance Formula
R = ρ × L / (T × W) × [1 + α × (T_amb - 25°C)]
- R: Resistance (Ω)
- ρ: Material resistivity (Ω·m)
- L: Trace length (m)
- T: Trace thickness (m)
- W: Trace width (m)
- α: Temperature coefficient (/°C)
- T_amb: Ambient temperature (°C)
Note: Temperature significantly affects resistance. Copper resistance increases by ~0.39% per °C.
Factors Affecting Resistance
Geometry
Resistance is inversely proportional to cross-sectional area (width × thickness) and directly proportional to length.
Material
Copper has excellent conductivity, but silver and gold offer lower resistance at higher cost.
Temperature
Higher temperatures increase resistance. PCBs can reach 70-85°C in normal operation.
Applications
Power Distribution
Calculate voltage drops in power supply rails and ground planes.
Signal Integrity
Minimize resistance in high-speed digital and RF circuits.
Current Sensing
Use known trace resistance for current measurement applications.