Enter the output voltage and the input voltage into the calculator to determine the Voltage Efficiency. 

Voltage Efficiency Formula

The following formula is used to calculate the Voltage Efficiency. 

Ev = OV / IV * 100
  • Where Ev is the Voltage Efficiency (%)
  • OV is the output voltage 
  • IV is the input voltage 

To calculate the voltage efficiency, divide the output voltage by the input voltage, then multiply by 100.

How to Calculate Voltage Efficiency?

The following two example problems outline how to calculate the Voltage Efficiency.

Example Problem #1:

  1. First, determine the output voltage. In this example, the output voltage is given as 75.
  2. Next, determine the input voltage. For this problem, the input voltage is given as 90.
  3. Finally, calculate the Voltage Efficiency using the equation above: 

Ev = OV / IV * 100

Inserting the values from above and solving the equation: 

Ev = 75/ 90 * 100 = 83.33 (%)


What factors can affect voltage efficiency in electrical systems?

Voltage efficiency can be influenced by several factors including the quality of electrical components, the length and material of the wiring, environmental conditions, and the load on the system. High-quality components and optimal design can minimize losses and improve efficiency.

Why is it important to calculate voltage efficiency?

Calculating voltage efficiency is crucial for designing efficient electrical systems, reducing energy consumption, and minimizing energy costs. It helps in identifying areas where improvements can be made and in ensuring that systems are operating as intended.

Can voltage efficiency exceed 100%?

No, voltage efficiency cannot exceed 100%. An efficiency of 100% would mean that there are no losses in the system, which is theoretically impossible due to inherent resistances and losses in any practical electrical system. Efficiencies above 100% indicate measurement errors or incorrect calculations.