BackFortyPower.com · Load Calculator

Off-Grid Load Calculator For Smarter Power Planning.

Estimate how much power your cabin, RV, homestead, workshop, or backup system needs before buying solar panels, batteries, inverters, wind turbines, portable power stations, or complete off-grid kits.

Start The Worksheet See Example Calculation

Estimate Daily Watt-Hours

Check Running Loads And Surge Loads

Plan Batteries, Solar, Inverters And Backup

Core Formula

The First Planning Number Is Daily Watt-Hours.

Daily watt-hours help you understand battery storage, solar recharge, inverter planning, and backup power needs before comparing equipment.

Basic Load Formula

Watts × Hours Per Day = Watt-Hours Per Day

1
List Every Appliance, Device, Pump, Tool, Charger, And Critical Load.
2
Estimate Running Watts And Daily Runtime For Each Item.
3
Identify Surge Loads From Motors, Compressors, Pumps, And Power Tools.
4
Use The Total To Plan Batteries, Solar, Inverter Capacity, And Backup Power.

Best Practice: Build the load plan first, then compare equipment. That single step helps prevent undersized systems, oversized purchases, and unrealistic expectations.