Off-Grid Load Calculator
Calculate your total energy needs for an off-grid system. Add devices by room, set usage hours, and determine your daily, weekly, and monthly power consumption including ghost loads and inverter overhead.
Add Devices
Select a room and device to add with standard wattage values, or add a custom device.
System Overhead
Ghost loads and inverter self-consumption add to your total. Adjust these defaults as needed.
Standby power consumed by devices when off. Typically 5-10% of total load.
Power the inverter uses to run itself, even with no load attached.
Results
Add devices and click calculate to see your energy requirements
How to Use This Calculator
1. Add Your Devices
Select a room from the dropdown to see common devices with standard wattage values pre-filled. You can also add custom devices with your own wattage values. Use a kill-a-watt meter for the most accurate readings.
2. Set Hours & Quantity
Adjust the hours per day each device runs and the quantity if you have multiples. For intermittent loads like a well pump, estimate the total runtime per day (e.g., 2 hours total).
3. Mark Simultaneous Use
Check the "simultaneous" box for devices that run at the same time. This determines your baseline power draw, which your inverter must handle continuously. This is critical for sizing your inverter.
4. Review Overhead
Ghost loads (5% default) account for phantom power draw from devices in standby. Inverter self-consumption (100W, 24h default) covers the inverter's own power needs. Adjust both values based on your specific equipment.
Need help designing your off-grid system?
Our team can review your load requirements and recommend the right equipment.