Generator Calculator Size

Introduction: Selecting the right generator size is crucial for ensuring a reliable power supply during outages. The Generator Calculator Size streamlines this process by providing recommendations for the optimal generator size based on power requirements, efficiency, and hours of operation.

Formula: The recommended generator size is calculated by dividing the power requirement by the efficiency percentage (converted to a decimal) and then multiplying the result by the hours of operation per day. This formula takes into account both the power demand and the expected efficiency of the generator.

How to Use:

  1. Enter the power requirement in watts.
  2. Input the generator efficiency as a percentage.
  3. Specify the hours of operation per day.
  4. Click the “Calculate” button to obtain the recommended generator size.

Example: For a power requirement of 5000 watts, a generator efficiency of 90%, and 8 hours of operation per day, the Generator Calculator Size might suggest a recommended generator size of 4444.44 watts.


  1. Q: Can I use this calculator for generators from different brands? A: Yes, the Generator Calculator Size provides a general estimation applicable to generators from various brands.
  2. Q: How does generator efficiency impact the recommended size? A: Higher efficiency results in a smaller recommended generator size, as it can produce more power with less fuel consumption.
  3. Q: Is the recommended generator size a strict requirement, or can I deviate slightly? A: The recommended size serves as a guideline. Deviations within a reasonable range are often acceptable based on specific needs and preferences.
  4. Q: Does the calculator account for factors like starting wattage for appliances? A: No, the calculator provides a basic estimation. Consider additional factors, such as starting wattage requirements, when selecting a generator.
  5. Q: Can I use this calculator for commercial generators as well? A: While designed for residential applications, the calculator can offer insights for commercial use. Complex commercial needs may require professional consultation.

Conclusion: The Generator Calculator Size is a valuable tool for individuals and businesses seeking to determine the optimal generator size for their power requirements. Use this calculator to make informed decisions and ensure a reliable backup power solution with the right-sized generator.

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