To calculate watts to voltage, different formulas, such as Power = I x V and Power = V squared / R, are used. These different physics formulas are then manipulated so that voltage is expressed in terms of certain other variables and power, which is given in watts.

In the formula Power = I x V, the power is given in watts, I is current in amperes and V is volts. The second formula that may be utilized to calculate watts to voltage is Power = V squared / R, where R is the resistance in ohms.

In one method, write the power formula as Power in watts = I x V. Divide both sides of the equation by I to arrive at the new equation as Power in watts / I = V.

An alternate formula is to multiply both sides of the power formula, which is Power = V squared / R to find Power x R = V squared. Take the square root of both sides to get the new equation in terms of voltage , which is V = the square root of (Power x R).

Instead of having to derive these voltage formulas, there are online watts to voltage calculators for use if the power in watts, current and resistance are known. For example, using the calculator provided by RapidTables and entering 8 watts = Power and 2 amps = current yields the calculated value for volts as 4 and resistance as 2 ohms.