Understanding Generator Power Ratings: What You Need to Know

Dec 04, 2025By Tonya Evinger
Tonya Evinger

When it comes to choosing a generator, understanding power ratings is crucial. These ratings tell you how much power a generator can produce and for how long. Making sense of these numbers will help you select the right generator for your needs.

What Are Generator Power Ratings?

Generator power ratings are measurements of the electrical output a generator can provide. They are typically expressed in watts (W), kilowatts (kW), or megawatts (MW). This rating helps determine the capacity of the generator to support electrical devices or systems during a power outage or in remote locations.

Generators are rated based on their maximum and continuous power outputs. Maximum power refers to the peak load a generator can handle for a short period, usually under an hour. Continuous power, on the other hand, is the load the generator can handle indefinitely.

generator power

Understanding Wattage Requirements

To make the most of your generator, you need to understand your wattage requirements. This involves calculating the total wattage of all the devices you plan to power with the generator. It's essential to consider both starting and running watts.

Starting watts are the extra watts needed for about three seconds to start motor-driven products like refrigerators or power tools. Running watts are the continuous watts needed to keep items running.

Calculating Total Wattage

To calculate your total wattage, list all the devices you plan to power and add their starting and running watts. This will give you an idea of the generator size you need. Remember, it's always a good idea to have a generator with a slightly higher power rating than your calculated total.

power calculation

Types of Generator Power Ratings

Generators come with different power ratings that indicate their intended use and capacity. The most common types include:

  • Standby Power: For emergency backup during power outages.
  • Prime Power: For regular use, usually in remote or off-grid locations.
  • Continuous Power: For constant and long-term use without interruption.

Understanding these ratings will help you select a generator that aligns with your specific requirements and usage patterns.

Choosing the Right Generator

When choosing a generator, consider both the power rating and the intended application. For home use during outages, a standby generator with an adequate power rating may suffice. For construction sites or remote locations, a prime or continuous power generator might be more appropriate.

generator types

In conclusion, understanding generator power ratings is essential for selecting the right generator for your needs. By knowing the difference between maximum and continuous power, calculating your wattage requirements, and considering the types of power ratings, you can make an informed decision. This ensures your generator will provide reliable power whenever and wherever you need it.