Cable Field Tool
Cable Calculator
Estimate amp rating, resistance, voltage drop, power loss, and load capacity. Always confirm final selection against Japanese standards, installation method, ambient temperature, grouping, and manufacturer data.
Reference estimate only. Check code tables, cable type, conduit/tray method, ambient temperature, grouping, and manufacturer data before installation.
Calculators
Electrical Calculation System
Choose what you need to find. Fields change automatically and results show the working.
Calculation Selector
Choose the target value
Use this as your main calculator for exam practice and site estimation.
Ohm’s Law
Voltage Drop
Wattage
3-Phase Power
Reference
Core Formula Cards
Fast revision formulas with simple meaning.
Ohm’s Law
V = I × R
Voltage = Current × ResistanceCurrent
I = V ÷ R
Use when voltage and resistance are known.Resistance
R = V ÷ I
Use when voltage and current are known.Power
P = V × I
Watts = Volts × Amps.Power Loss
P = I² × R
Heat loss through resistance.3-Phase
P = √3 × V × I × PF
Balanced three-phase real power.Energy
E = P × t
Joules = Watts × seconds.Voltage Drop
Vd = I × R
Voltage lost through resistance.