# How to convert ohms to volts

How to convert electric resistance in ohms (Ω) to electrical voltage in volts (V).

You can calculate volts from ohms and amps or watts, but you can't convert ohms to volts since ohm and volt units do not measure the same quantity.

### Ohms to volts calculation with amps

According to ohm's law, the voltage V in volts (V) is equal to the current I in amps (A) times the resistance R in ohms (Ω):

*V*_{(V)} = *I*_{(A)} × *R*_{(Ω)}

So volts are equal to amps times ohms:

volts = amps × ohms

or

V = A × Ω

#### Example

Calculate the voltage in volts when resistance is 25 ohms and the current is 0.2 amps.

The voltage V is equal to 0.2 amps times 25 ohms, which is equal to 5 volts:

*V* = 0.2A × 25Ω = 5V

### Ohms to volts calculation with watts

The power *P* is equal to the voltage *V* times the current
*I*:

*P* = *V *×* I*

The current *I* is equal to the voltage *V* divided by the
resistance *R *(ohm's law):

*I* = *V* / *R*

So the power *P* is equal to

*P* = *V *×* V / R* = *V *
^{2} / *R*

So the voltage V in volts (V) is equal to the square root of the power P in watts (W) times the resistance R in ohms (Ω):

__________________

*V*_{(V)} = *√P*_{(W)} × *R*_{(Ω)}

So volts are equal to the square root of watts times ohms:

volts = √watts × ohms

or

V = √W × Ω

#### Example

Calculate the voltage V in volts when the resistance is 12.5Ω and the power is 2 watts.

The voltage V is equal to the square root of 2 watts times 12.5 ohms, which is equal to 5 volts:

*V* = √2W × 12.5Ω = 5V

How to convert volts to ohms ►