Cable Resistance and Voltage Drop Calculator
How much voltage does your cable lose?
Uses copper at about 20°C. Hot cable has more resistance. Everything is worked out in your browser. Nothing is saved or sent anywhere.
1. The cable
2. The load
3. Results
How it was worked out
What this does and doesn't tell you
- Check the cable's current rating too. Low drop doesn't mean the cable can carry the current safely.
- Some cable is sold by outside size. Use the copper area in mm².
- 240V AC mains can kill. In Australia, work on household mains wiring must be carried out by a licensed electrician. Low-voltage DC systems can still deliver very high current.