Estimate the inverter size needed for appliances, tools, motors, pumps, RV loads, solar systems, battery backup, and off-grid power. Calculate continuous watts, surge watts, VA, battery current draw, safety margin, inverter load percentage, and recommended inverter size.
Running load:
The calculator totals the continuous running watts of the loads you want to power.
Surge load:
It checks starting or surge watts so the inverter can handle motor startup and short high-power demands.
Battery draw:
It estimates DC battery current from AC load watts, battery voltage, and inverter efficiency.
An inverter size calculator helps estimate the wattage rating needed for solar systems, battery backup, RVs, cabins, off-grid systems, vehicles, and portable power setups.
It can help with refrigerators, microwaves, pumps, tools, lights, outlets, computers, chargers, medical devices, appliances, and motor loads.
Your result shows recommended inverter watts, recommended surge watts, load VA, battery current draw, existing inverter load percentage, estimated battery runtime, required battery amp-hours, safety margin, continuous load factor, and detailed load row totals.
Add the running watts of the loads you want to power, then add a safety margin. Also check starting or surge watts for motors, pumps, compressors, and appliances.
Use the refrigerator running watts and starting surge watts from the nameplate or manual. Refrigerators often need a higher surge rating than their running wattage.
Battery voltage affects DC current draw. A 12V system draws about twice the current of a 24V system for the same AC load, before efficiency losses.
No. This calculator gives a planning estimate. Final inverter selection should account for surge rating, waveform type, battery voltage, wiring size, fuses, disconnects, grounding, ventilation, manufacturer limits, and electrical code.