🔋 Off-Grid Load Calculator
List your appliances with their watts, quantity and daily run-time to get your total daily energy use in watt-hours.
| Appliance | Watts | Qty | Hours/day | Wh/day | |
|---|---|---|---|---|---|
| 200 | |||||
| 3,600 | |||||
| 240 |
Total daily energy
4,040 Wh
4.04 kWh/day
Per month · year
123 · 1,476 kWh
Daily energy is the sum of each appliance's watts × quantity × hours run per day. This total is the starting point for sizing an off-grid system: feed it into the battery-bank and solar-panel calculators. Preset wattages are typical starting points — real appliances vary, and motor-driven ones (fridges, pumps) cycle on and off, so use their average daily run-time. 🔒 In your browser.
How the off-grid load calculator works
Sizing any off-grid or solar system starts with one number: how much energy you use in a day. The tool adds up each appliance as watts × quantity × hours run per day, giving watt-hours, then totals them for your daily load in Wh and kWh. That figure feeds directly into the battery-bank and solar-panel calculators.
The realistic part is the run-time. Appliances that cycle — fridges, freezers, pumps, heating and cooling — are only drawing power some of the time, so use the average hours they actually run per day, not the 24 they're plugged in. The preset wattages are typical starting points; check your own appliances' labels for accuracy.
Frequently asked questions
How do I calculate my daily energy use?
For each appliance, multiply its watts by how many you have and by the hours it runs per day to get watt-hours, then add them all up. A 150 W fridge running an effective 8 hours is 1,200 Wh; sum every device for your daily total.
How do I size an off-grid solar system?
Start here with your daily load in watt-hours. Then size the battery bank (load × days of autonomy ÷ depth of discharge) and the solar array (enough daily kWh to replace the load plus losses). This tool produces the input the other two need.
Should I use running watts or hours plugged in?
Running watts and actual run-time. A fridge is rated maybe 150 W but only its compressor running counts, perhaps 8 equivalent hours a day — not 24. Using plugged-in hours hugely overestimates the load and your system cost.
What's the difference between watts and watt-hours?
Watts is the rate of power draw; watt-hours is energy — watts multiplied by time. A 100 W device for 3 hours uses 300 Wh. Off-grid systems are sized on watt-hours (energy) per day, which is what this tool totals.
How much do common appliances use?
Roughly: LED bulb 10 W, laptop 60 W, TV 100 W, fridge 150 W (running), microwave 1,000 W. These vary by model, so the presets are starting points — use your appliance's actual label or a plug-in meter where you can.