Free backup & solar calculators
Work out inverter size, battery backup time and solar capacity using your appliance load and clear loss settings.
From appliance load to backup time
- Start with the calculator closest to your question.
- Replace the example values with your own details.
- Open the calculation steps and read the assumptions.
- Save or print the result before checking the final decision.
Choose a calculator
Home Electrical Load Calculator
running and starting load for backup appliances
Open calculator →Inverter Size Calculator
an inverter VA range from watts, surge, power factor and margin
Open calculator →Battery Backup Time Calculator
battery runtime with depth-of-discharge and inverter losses
Open calculator →Required Battery Capacity Calculator
required Ah for a desired backup time
Open calculator →UPS Runtime Calculator
UPS runtime from its battery bank and actual load
Open calculator →Inverter and Battery Combined Planner
inverter capacity and battery Ah in one joined workflow
Open calculator →Solar Panel Size Calculator
an array and panel count from daily energy and local peak sun hours
Open calculator →Solar Battery Size Calculator
a battery bank for daily solar-supported energy and autonomy
Open calculator →Solar Savings Estimator
first-year savings, simple payback and a ten-year scenario
Open calculator →Inverter size and battery time are different
The inverter VA rating must handle the running load and starting surge. Battery Wh or Ah helps estimate how long that load can run after losses.
Before you calculate
Why are watts and VA different?
Work out inverter size, battery backup time and solar capacity using your appliance load and clear loss settings.
How does battery depth of discharge matter?
The result shows the exact formula and the settings used.
Why is solar yield location-specific?
Use the answer for planning, then check the important label, specification or official record.