Free sizing tool
Off-Grid Solar Calculator
Enter how much power you use in a day and this tool sizes your solar array, your battery bank, and your inverter. It is built for beginners, so you do not need to know any of the formulas. We do the math and hand you real numbers.
How to use this
- Add up roughly how many watt-hours you use in a day. A small van might use 500 to 1,000 Wh, a cabin 2,000 to 5,000 Wh.
- Set your average daily sun hours. Four is a safe middle-ground for most of the US.
- Pick days of autonomy, meaning how long the battery should last with no sun.
- Choose your system voltage and your biggest single appliance draw, then hit Calculate.
Your numbers
Not sure? A fridge, lights, and charging a few devices is around 1,000 to 2,000 Wh per day.
Leave blank and we will assume a sensible default.