Browser utility · No upload
Off-Grid Calculator
Estimate solar array size, battery runtime, and cable gauge — free, private, and instant.
Runs locally in your browser — your input is never uploaded or stored.
About this tool
Off-Grid Calculator lets you estimate solar array size, battery runtime, and cable gauge without installing an app or creating an account. Turn daily load and sun-hour assumptions into a practical first-pass system estimate.
Size a solar setup for an RV, cabin, or backup system by estimating panels, battery capacity, wire gauge, and rough cost from your daily energy use.
How it works
- Enter or choose your values
- Review the instant result
- Copy or download the result
Frequently asked questions
How do I use Off-Grid Calculator?
Enter or choose your input in the tool above. The result updates immediately or appears when you select the action, ready to copy or download.
Is this accurate enough to buy equipment?
It gives a solid first-pass estimate for planning; confirm final sizing with an installer or manufacturer specs before purchasing.
Is Off-Grid Calculator free, and is my data private?
Yes. Off-Grid Calculator is free with no account or watermark, and it runs entirely in your browser so your input is never uploaded, stored, or shared.
Does it work on phones and tablets?
Yes. It works in current browsers on Android, iPhone, iPad, Windows, macOS, and Linux.