Free engineering-grade calculations for your home or business: system size, panels, inverter, battery, cable thickness and line loss — for any location worldwide.
Answer a few questions — our engine does the rest.
Powerful tools to design your perfect solar system
kW and panel count from your usage
Open →How many panels your roof needs
Open →Continuous rating and startup surge
Open →Lithium vs lead-acid, sized for backup
Open →Wire thickness and line loss
Open →Best orientation for your latitude
Open →Simple steps to get your accurate solar design
Your electricity usage or appliance list, and your location.
Local sun hours, losses and surge factors are applied automatically.
Standard formulas size every component of the system.
A complete equipment list with best-practice suggestions — print or save.
Your result covers everything an installer would quote — so you walk in informed:
We sell nothing and take no commissions from brands or installers.
Sun-hour data by city, with a latitude model covering the entire globe.
The same formulas professionals use — surge, losses and headroom included.
Calculations run in your browser. No account, no tracking of your inputs.