Free Tool · No account required
How many solar panels do you need?
List what you need to power, set your battery and voltage, and pull real sun data for your land, then get panel, battery, inverter, and charge-controller sizing with a cost estimate. The same math an installer runs, free and in your browser.
- Free for everyone
- No account, no signup
- Real NREL sun data
- Made for off-grid living
Solar panels
count + total watts
Battery bank
amp-hours + units
Inverter
continuous watts
Charge controller
amps + MPPT/PWM
What it does
From "how many panels?" to a parts list.
Start from your real loads
Add appliances from a preset library of fridge, well pump, mini-split, Starlink, and power tools, or enter your own. Watts × hours × quantity rolls up into daily kWh and peak demand.
Real sun data, not guesses
Drop in your build location and the planner pulls month-by-month solar irradiance from NREL’s free PVWatts model, then sizes for the worst month so the system carries through winter.
Sizes the whole system
Panels, battery bank, inverter, and charge controller, sized together from your load, autonomy days, system voltage, and battery chemistry (LiFePO4, AGM, or lithium-ion).
Ballpark the cost
Matches your sizing to representative real-world gear so you get an itemized equipment estimate, a starting budget before you talk to an installer or order parts.
How it works
Three steps to a sized system.
01
List your loads
Add appliances from the preset library or enter your own. The planner totals your daily energy use and peak demand as you go.
02
Set system + location
Pick your system voltage, battery type, panel size, and days of autonomy. Add your build location to pull real NREL sun data for your area.
03
Read your sizing
Get panel, battery, inverter, and charge-controller sizing plus an itemized cost estimate, instantly, and saved in this browser for next time.
Why it's free
Built for off-grid living, not upsells.
Off Grid Hubs makes free tools for people building a life off the grid. This planner runs entirely in your browser on free, public NREL solar data, with no quote forms, no email wall, no selling your info to installers. Use it to sanity-check a quote, plan a budget, or just figure out how much sun your land really gets.
Common questions
Off-grid solar, answered.
Ready to size your system?
Free, no signup, and your inputs save right in this browser.
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