Cable Size Calculator
Estimate cable size from current, voltage, length, material, and allowable voltage drop. Returns minimum mm² and nearest standard size.
A
m
V
%
Calculated Minimum 1.59 mm²
Recommended Standard Size 2.5 mm²
Target Voltage Drop 6.9 V
Frequently Asked Questions
- A simplified cable size calculation uses current, run length, conductor material, system voltage, and allowable voltage drop to estimate the minimum cross-sectional area.
- Longer cables create more resistance, which increases voltage drop. That usually means you need a larger conductor size for the same current.
- Voltage drop is the amount of voltage lost along a cable because of its resistance. Too much voltage drop can reduce equipment performance and increase heating.
- Copper usually needs a smaller cross-sectional area than aluminum for the same current and voltage drop, because copper has lower resistivity.
- Yes, this simplified model is useful for many DC and low-voltage planning cases. Always verify with your electrical code and final installation conditions.
- Common metric cable sizes include 1.5, 2.5, 4, 6, 10, 16, 25, 35, 50, 70, and 95 mm², though exact availability depends on region and application.
- No. It is a planning tool, not a substitute for local electrical code, insulation temperature ratings, conduit fill rules, grouping factors, or final engineer review.
- Choose the next standard size above the calculated minimum so the installed cable stays within your voltage drop target.