Home Calculators Amps Calculator

Amps Calculator

Calculate amps, volts, watts, ohms, and kVA using Ohm's Law and electrical power formulas. Supports DC, single-phase AC, and three-phase AC systems.

Ohm's Law · DC & AC · 3-Phase · Power factor · Wire sizing · kVA / kW

What do you want to find?

Select the unknown variable — enter the other two

System Type
Known Values
Live Result
—
A
I (Amps)—
V (Volts)—
P (Watts)—
R (Ohms)—
Ohm's Law Formulas
V = I × RVoltage
I = V / RCurrent
R = V / IResistance
P = V × IPower
P = I² × RPower
P = V² / RPower
I = P / VCurrent
I = √(P/R)Current
V = P / IVoltage
V = √(P×R)Voltage
R = V²/PResistance
R = P/I²Resistance
Common Voltages
US Household120 V AC
US Appliances240 V AC
EU/UK Household230 V AC
3-Phase US208 / 480 V
Car battery12 V DC
USB5 V DC
AA battery1.5 V DC
AWG Wire Capacity
AWG 1415 A
AWG 1220 A
AWG 1030 A
AWG 840 A
AWG 655 A
AWG 470 A
AWG 295 A
AWG 1/0125 A