OffGridFoundry.com
Solar Panel Size Calculator
Size your off-grid solar system accurately — based on real NREL sun hour data.
▸
Daily Appliances
Daily Appliances
| Appliance | Watts | Hrs/day | Qty | Wh/day |
|---|
▸
Location & System Settings
Location & System Settings
US Region / Climate Zone
Peak sun hours
— select region above
— select region above
NREL annual avg
System voltage
Days of autonomy
Days running without sun
Days running without sun
days
Battery depth of discharge
System efficiency
Wiring + MPPT + inverter losses
Wiring + MPPT + inverter losses
Recommended Solar Array
—W
Enter appliances and select a region to calculate
▸ Calculation Breakdown
| Daily consumption | — |
| Peak sun hours | — |
| System efficiency | — |
| Solar needed (raw) | — |
| +25% design margin | — |
| Recommended solar | — |
| 400W panels needed | — |
▸ Battery & Controllers
| Battery bank | — |
| Battery Ah | — |
| MPPT charge controller | — |
| Inverter size | — |
▸ Est. Component Cost (US, 2025)
| Solar panels | — |
| Battery bank | — |
| MPPT controller | — |
| Inverter | — |
| Balance of system | — |
| Estimated total (DIY) | — |
Estimates for planning only. Actual requirements vary by shading, tilt, equipment, and local code. Consult a licensed installer before purchasing.