Electrical Calculators
Watts, amps, voltage drop, circuit loads and generator sizing. Every result is a preliminary calculation — the NEC as adopted locally and a qualified electrician have the final word.
Most used
- Voltage Drop CalculatorVoltage drop and percent drop for copper or aluminum conductors by AWG size and length.
- Watts to Amps & Amps to Watts CalculatorConvert watts to amps or amps to watts for single- and three-phase circuits.
- Wire Size Calculator (Voltage Drop)Smallest conductor that keeps voltage drop under your limit.
Power
Wiring
- Extension Cord Voltage Drop CalculatorVoltage at the tool for an extension cord gauge, length and load.
- Voltage Drop CalculatorVoltage drop and percent drop for copper or aluminum conductors by AWG size and length.
- Wire Size Calculator (Voltage Drop)Smallest conductor that keeps voltage drop under your limit.
Circuits
Guides
Questions
Why doesn’t the wire size calculator give an ampacity answer?
Ampacity depends on insulation rating, terminals, ambient temperature, bundling and installation method under NEC 310. We calculate voltage drop precisely and tell you to check ampacity separately rather than guess.