Backup Power Calculators
Size generators, essential loads, portable power stations, UPS systems, whole-home batteries, and compare backup ownership costs.
Generator Size Calculator
Estimate generator capacity from running watts, additional starting surge, simultaneous load, and design margin.
CALCEssential Load Calculator
Estimate peak backup power and daily energy required for selected essential household loads.
CALCGenerator Fuel Use and Cost Calculator
Estimate fuel consumption and operating cost for a generator over a selected runtime and outage duration.
CALCPortable Power Station Runtime Calculator
Estimate usable energy and runtime for a portable power station at a selected continuous load.
CALCUPS Runtime Calculator
Estimate backup duration for a UPS from battery energy, load, conversion efficiency, and reserve allowance.
CALCWhole-Home Battery Size Calculator
Estimate nominal battery capacity required for a selected outage duration and share of whole-home electricity use.
CALCGenerator vs Battery Backup Cost Calculator
Compare simplified multi-year ownership cost for a standby generator and a home battery system.
Planning with backup power calculators
Use several related tools rather than relying on one result. Energy systems are constrained by both energy and power, and final equipment choices depend on climate, operating schedules, manufacturer limits, utility rules, and local codes.