What do you need to power? Make a list.

Ask yourself what you will need to power during an electrical outage: just appliances and lights? Computers and home electronics, too? Some families have in-home medical equipment that is a priority, while others need to ensure they have enough power to keep stocked food supplies on ice.

If you need a generator for recreational or job site usage, list out the tools or appliances you will want to use at the same time. Will you need to power work lights along with your tools? What about a radio? On camping or fishing trips, how many outdoor cooking, heating or entertainment appliances or accessories will you and your family or friends be using at once?

Determine what it takes to start each appliance.

Ensure you'll be able to start (not simply run) your appliances. The "starting wattage" is the amount of wattage needed to start an appliance with a motor; and it may be two to three times the wattage required to run the appliance. If you have owner's manuals, check for your appliances' listed start-up wattages (vs. the running wattage or the rated wattage). If you don't have owner's manuals, use our wattage calculator to estimate your power needs.

Calculate your total power needs.

It's a two part equation. First, add up all the "running wattage" for all the items you wish to power simultaneously. This equals the total running watts your generator needs to produce simply to run your equipment. Next, add to that total the highest of the "starting wattages" you wrote down in step 2, above. Now you know how much power you need to start and run your appliances and equipment!

With the knowledge you now have about your power needs, you can comparison shop for generators within your wattage requirement.