How to Calculate Wattage for Power Inverters

There are a lot of different power inverters on the market. There are huge ranges in power levels that start around 150 watts, all the way to 3000 watts or larger. How do you know which power inverter is right for you? Well, the first thing to do is calculate the wattage for each device. I have included a power inverter wattage calculator worksheet to help you get started. Here is a little information to help you calculate a devices wattage.

Calculate power inverter wattage requirements

We have added a new real time power inverter calculator in our tools section.

Almost every AC powered device has an electrical requirements tag located on its chord or surface. This will usually have Input Voltage and Amperage. It is important to note that some devices have output voltage and amperage which we will not use in these calculations.
I have included a couple of sample pictures for you to reference.

On the calculation sheet, I think it is important to calculate surges based on the type of device you are running. Notice motors are devices which usually have large surges, so account for this. These will usually need to be within the continuous rating of the power inverter.

Also realize that items like Microwaves may be listed as 800 Watts, but that is only cooking power. The electrical requirements can be much higher. Check the label.

Once you have completed the  Power Inverter Wattage Calculator Worksheet you will have a good idea of how many watts you need. I always suggest buying one size larger than required power inverter, unless you are purchasing the Sine Wave 3000 Watt Power inverter

I hope this has helped you calculate the overall wattage requirements for your Power Inverter. Feel free to visit Outside Supply or call 1-866-874-4983 with any questions. It will also be important to determine if you need a modified sine power inverter or true sine wave power inverter as well. You can also see our article and video on our blog explaining the difference between true sine wave inverters and their cheaper modified sine cousins.

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