Wire Size Calculator
Calculate proper wire gauge based on current, voltage drop, cable length, and conductor material
Calculator
Enter the current, voltage, cable length, and acceptable voltage drop to determine the recommended wire size.
About the Wire Size Calculator
The Wire Size Calculator helps you determine the correct electrical wire gauge based on current load, cable length, voltage level, and allowable voltage drop. It supports both copper and aluminum conductors, providing accurate sizing recommendations for safe and efficient electrical installations.
What You Can Calculate
- Required Cable Cross-Section (mm²): Based on load current, conductor resistivity, and voltage drop limits.
- Voltage Drop: Estimate the expected voltage loss along the cable run.
- Recommended AWG Size: Matches your calculated cross-section to the nearest standard AWG wire size.
- Copper vs. Aluminum Sizing: Compare conductor performance based on resistivity differences.
Formulas Used in the Calculator
The calculator uses standard electrical engineering equations for conductor sizing and voltage drop:
- Voltage Drop: Vdrop = I × R × 2 × L
- Maximum Conductor Resistance: Rmax = Vallowed / (2 × L × I)
- Required Cross-Section: A = ρ / Rmax
- Conductor Resistivity: Copper = 1.724×10⁻⁸ Ω·m; Aluminum = 2.82×10⁻⁸ Ω·m
How to Use the Calculator
- Select the conductor material (copper or aluminum).
- Enter the load current, system voltage, and cable length.
- Choose the allowable voltage drop percentage.
- The calculator instantly displays the required cross-section and recommended AWG size.
Applications of Wire Sizing
Proper wire sizing is essential for residential, commercial, and industrial electrical installations. Engineers use these calculations to ensure safe conductor temperatures, minimize voltage loss, and maintain compliance with electrical standards for feeders, branch circuits, motors, and long cable runs.