Ohms to Watts Calculator
Convert resistance and either voltage or current to power in watts.
Select either voltage or current.
How to Convert Ohms to Watts
For converting ohms (Ω) to watts (W), you need either voltage (V) or current (I). This comes from Ohm’s Law (V = I × R) and the power formula (P = V × I). For more information on power, refer to the Wikipedia page on Watt.
Ohms to Watts Formulas
To calculate power (P) in watts based on resistance (R) in ohms, you can use one of the following formulas:
If Voltage (V) is Known:
P = V² / RIf Current (I) is Known:
P = I² × RQuick Trick: Use the formula that corresponds to the known value (Voltage or Current)!
Understand the Conversion
To calculate power in watts from resistance in ohms, you need either the voltage or the current:
- If you know the voltage (V), use: P = V² / R
- If you know the current (I), use: P = I² × R
Simply input the known values and use the appropriate formula to calculate the power.
Example
Imagine you have the following measurements:
- Voltage entered: 12 V
- Resistance entered: 4 Ω
Here’s how we figure it out:
Applying Formula:
Formula: P = V² / R
Calculation: P = (12 V)² / 4 Ω = 144 / 4 = 36 W
Answer: 36 watts
What Do These Terms Really Mean?
Ohm (Ω) – A Unit of Resistance
Ohms are a standard unit of resistance used to measure electrical resistance. One ohm is the resistance that allows one ampere of current to flow with one volt of electrical potential.
Watt (W) – A Unit of Power
Watts are a standard unit of power used to measure electrical power. One watt is equal to one joule per second.
