Enter your total wattage, voltage, and starting wattage into the calculator to determine the required generator size.

Generator Size Calculation Formula

The following formula is used to calculate the required generator size. 

Generator Size = (Total Wattage + Starting Wattage) / Voltage

Variables:

  • Total Wattage is the combined wattage of all devices (W)
  • Starting Wattage is the additional wattage required to start certain devices (W)
  • Voltage is the operating voltage of the generator (V)

To calculate the generator size, add the total wattage and starting wattage, then divide by the voltage.

What is Generator Size Calculation?

Generator size calculation refers to the process of determining the appropriate generator size based on the total wattage of the devices you need to power and their starting wattage. This ensures that the generator can handle the power requirements of all connected devices without overloading.

How to Calculate Generator Size?

The following steps outline how to calculate the generator size using the given formula.

  1. First, determine the total wattage of all the devices you need to power.
  2. Next, determine the starting wattage required for any devices with high startup power needs.
  3. Determine the voltage of the generator you are considering.
  4. Use the formula from above: Generator Size = (Total Wattage + Starting Wattage) / Voltage.
  5. Finally, calculate the generator size by plugging in the values.
  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.

Total Wattage = 3000W

Voltage = 120V

Starting Wattage = 500W

FAQ

1. What is total wattage?

Total wattage is the sum of the wattage of all devices you plan to power with the generator.

2. How is starting wattage different from total wattage?

Starting wattage is the additional power required to start certain devices, which is typically higher than their running wattage.

3. How often should I use the generator size calculator?

It’s helpful to use the generator size calculator whenever you add new devices or change your power requirements to ensure your generator can handle the load.

4. Can this calculator be used for different voltages?

Yes, you can adjust the voltage field to match the operating voltage of the generator you are considering.

5. Is the calculator accurate?

The calculator provides an estimate of the required generator size based on the inputs provided. For exact figures, it’s best to consult a professional or the generator manufacturer.