Enter the resistance and current into the calculator to determine the power in watts. This calculator can also evaluate any of the variables given the others are known.

Ohms To Watts Formula

The following formula is used to calculate power in watts from resistance in ohms and current in amperes.

P = I^2 * R


  • P is the power in watts (W)
  • I is the current in amperes (A)
  • R is the resistance in ohms (Ω)

To calculate the power in watts, square the current in amperes and multiply the result by the resistance in ohms.

What is Ohms To Watts?

Ohms and Watts are units of measurement used in electricity. Ohms measure electrical resistance, indicating how much a device or material resists the flow of electric current. Watts, on the other hand, measure power, indicating the rate at which energy is used or produced. The relationship between these two units is defined by Ohm’s Law and the Power Law, which state that power (in watts) equals the square of the current (in amperes) times the resistance (in ohms). Therefore, converting ohms to watts involves knowing the current involved in the circuit.

How to Calculate Ohms To Watts?

The following steps outline how to calculate the Ohms To Watts using the formula P = I^2 * R.

  1. First, determine the current in amperes (I).
  2. Next, determine the resistance in ohms (R).
  3. Next, square the value of the current (I^2).
  4. Multiply the squared current (I^2) by the resistance (R).
  5. Finally, calculate the power in watts (P).
  6. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge.

current (I) = 5 A

resistance (R) = 10 Ω