Home Energy Desk tools
Backup Power Calculators
Size generators, essential loads, portable power stations, UPS systems, whole-home batteries, and compare backup ownership costs.
Explore every backup power calculators
Generator Size Calculator
Estimate generator capacity from running watts, additional starting surge, simultaneous load, and design margin.
Essential Load Calculator
Estimate peak backup power and daily energy required for selected essential household loads.
Generator Fuel Use and Cost Calculator
Estimate fuel consumption and operating cost for a generator over a selected runtime and outage duration.
Portable Power Station Runtime Calculator
Estimate usable energy and runtime for a portable power station at a selected continuous load.
UPS Runtime Calculator
Estimate backup duration for a UPS from battery energy, load, conversion efficiency, and reserve allowance.
Whole-Home Battery Size Calculator
Estimate nominal battery capacity required for a selected outage duration and share of whole-home electricity use.
Generator vs Battery Backup Cost Calculator
Compare simplified multi-year ownership cost for a standby generator and a home battery system.
Generator Fuel Tank Runtime Calculator
Estimate generator runtime from fuel-tank size and fuel-consumption rate at a selected electrical load.
Solar Generator and Portable Power Station Size Calculator
Estimate portable power-station battery capacity, inverter rating, solar input, panel quantity, and recharge time for selected daily loads.
How to use these tools
Choose the calculator that matches your decision, enter values from equipment labels, utility bills, manuals, or verified specifications, and test more than one scenario. Calculator results are planning estimates. Confirm electrical, structural, HVAC, battery, and code-sensitive decisions with qualified professionals and applicable local requirements.