How to convert amps to ohms

How to convert electric current in amps (A) to resistance in ohms (Ω).

You can calculate ohms from amps and volts or watts, but you can't convert amps to ohms since ohm and amp units represent different quantities.

Amps to ohms calculation with volts

The resistance R in ohms (Ω) is equal to the voltage V in volts (V), divided by the current I in amps (A):

R(Ω) = V(V) / I(A)

So

ohm = volt / amp

or

Ω = V / A

Example

What is the resistance of an electrical circuit that has voltage supply of 12 volts and current flow of 0.3 amp?

The resistance R is equal to 12 volts divided by 0.3 amp:

R = 12V / 0.3A = 40Ω

Amps to ohms calculation with watts

The resistance R in ohms (Ω) is equal to the power P in watts (W), divided by the square value of the current I in amps (A):

R(Ω) = P(W) / I(A)2

So

ohm = watt / amp2

or

Ω = W / A2

Example

What is the resistance of an electrical circuit that has power consumption of 30W and current flow of 0.5 amp?

The resistance R is equal to 30 watts divided by the squared value of 0.5 amp:

R = 30W / 0.5A2 = 120Ω

 

Ohms to amps calculation ►

 


See also

Write how to improve this page