Free tools
Home backup calculators
Three free tools that share one library of 140 typical household loads. Pick the question you have tonight, search your fridge, router or well pump, and get the number before you shop.
- 3calculators
- 140household loads
- 13categories
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Load CalculatorFor a portable power station
Add the things you need running and see how many days a 2,048 Wh battery lasts, at 90 percent usable.
- Average watts
- Watt hours per day
- Days on your battery
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Generator Sizing CalculatorFor a standby or portable generator
Add your list and see the running total, the starting peak and the generator size range to look for.
- Running watts
- Starting watts
- Generator size
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Solar Panel CalculatorFor panels that refill a battery
Set your peak sun hours and see the panel watts you need and how long your panels take to recharge a battery.
- Watt hours per day
- Panel watts needed
- Recharge time
How to use them
- 1Search the library and tap the things you need running, like a refrigerator, a WiFi router or a CPAP.
- 2Switch each load on, then adjust its watts and duty to match the nameplate if you have it.
- 3Read your results in the dark panel. They update as you change the list.
About these numbers. Every preset is a typical estimate from DOE, ENERGY STAR and generator maker guides, not a measurement of your house. Check the nameplate on anything you depend on.