Generator Wattage Calculator – Find Out How much Power You Need

This calculator will help you estimate how much power you need for your appliances, so you know what kind of generator to purchase.

The numbers I used are averages, they may vary depending on your equipment.

To use the calculator, change the “How many?” field to add one or more of a particular item. At the bottom, you will find your wattage estimation

13 thoughts on “Generator Wattage Calculator – Find Out How much Power You Need”

  1. So, if I have video and film production lights that go from 250-300 watts to 4k watts, and 120v to 240v how do I calculate what size generator I need? For example, I am looking at 10k and 12k hybrid generators (gas or propane), like these: DuroMax XP10000E 10000 Watt 16 HP Generator DuroMax XP12000E 12000 Watt for aroung $1,000.00. Say, I am going to light a set using three 4k lights which equals 12,000 watts is that one generator going to run those lights. Correct? Please advise. Thank you, Duker…

    • Hi Duker, That won’t be enough, you have to look at Running watts, not starting or surge watts. If you really need to power 12K watts of lamps, you should look at 15,000 Running watts generators, like the duromax XP15000EH, or generac’s GP15000E. Also consider the advertised run-time at half load to give you an idea of just how much time you will be able to run your setup. Hybrid /dual-fuel generators will give you more flexibility.

  2. I live in the hill there is no electricity..what would i need to have a small regular tv and lights. In the house maybe a small appliance going.

  3. I have a well I need to supply power to incase of power outage, either caused by storm outages, or PG&E shutting off the grid for “safety”.
    your calculator indicated that my need would be to supply 5800W of power.

  4. Hi –
    I’m in the same boat as Robert, trying to get a generator in case PG and E turns off power
    My fridge is 115 V/10 amps so I know running watts is 1150 …I am not sure how to find startup watts. Since my device running watts are so much higher than average, I dont want to use number (2000W) that I see quoted online for average start up watts
    Can you help?

  5. Hi. I have a converted a container into a cafe and require a generator to run it from as there is no power supply. Any advice on whether a 15kva generator will be enough to run everything and something which lasts for 15hrs per day

  6. If I hook up 12 – 12V – 6amp LED transformers what size, rechargeable, generator would I need to run it for 8 hrs.?

  7. I have a 50″ 4k tv and a portable trek antenna’ I wanna tailgate for about 8 hrs, what size generator what i need?


  8. I have a well pump, electric hot water heater, a washer electric dryer, microwave oven, 2 televisions, LED house lighting, a dishwasher, and an auxiliary pump to bring water from the river to a large storage tank, and a hot tub.

    I realize all of these items are unlikely to be running at the same time. I get it that in an emergency, I may choose to leave the breakers off for some of my circuits so I can choose what will get power. I’m thinking of getting a 7,000 – 9000 watts dual fuel generator which will be run on propane. Please advise. Thanks

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