Design Your Off-Grid Solar System
Free, fast, no signup required. Enter your appliances, pick your location, and get a complete solar + battery system design in seconds — powered by real NREL solar data.
Start Designing →☀️ Powered by NREL solar data | ⏱ Takes 2 minutes | 🔋 Battery, panels, inverter included
Why Use SolarCalc.fyi?
Step-by-Step Wizard
Tell us what appliances you want to run. We handle the math — from daily energy usage to full system specs.
Real NREL Solar Data
Your location matters. We fetch real Peak Sun Hours from the National Renewable Energy Laboratory database. No estimates, no guesswork.
Complete System Design
Battery bank (LiFePO4, AGM, or lead-acid), solar panels, inverter, and charge controller — all sized for your specific needs.
Cost Estimates
Get realistic pricing for your entire system, including the 30% federal tax credit and recommended equipment.
Nameplate Photo Reader
Don't know an appliance's wattage? Snap a photo of its nameplate — our tool helps you read the specs.
Email Your Results
Save your system design and have it emailed to you. Full component specs, wiring diagrams, and cost breakdown.
How It Works
Add Your Appliances
Select from 20+ common off-grid appliances (lights, fridge, TV, laptop, water pump, etc.) or add custom ones. We calculate your total daily energy usage in watt-hours.
Choose Your Location
Type your city name. We fetch real Peak Sun Hours from the NREL National Solar Radiation Database — the same data professional installers use.
Configure Your System
Choose battery chemistry (LiFePO4, AGM, or lead-acid), system voltage (12V, 24V, or 48V), and days of autonomy. Smart defaults for beginners, full control for experts.
Get Your Results
Instant system design with solar array size, battery bank capacity, inverter wattage, charge controller specs, and cost estimates — all in one report.
Learn About Off-Grid Solar
New to solar? Start with our comprehensive guides, written by industry professionals.
Off-Grid Solar Basics
New to off-grid solar? Start here. Learn how systems work, what components you need, and how to size everything.
Read Guide →Panel Sizing Guide
Step-by-step instructions for calculating the exact number of solar panels your off-grid system needs.
Read Guide →Battery Comparison
LiFePO4 vs AGM vs flooded lead-acid. Compare costs, lifespan, and total cost of ownership for each chemistry.
Read Guide →Solar ROI Guide
How long does solar take to pay off? State-by-state payback periods, off-grid vs grid-tied analysis.
Read Guide →Solar Myths Debunked
12 common solar myths busted with real data. Do panels work in winter? Is solar too expensive? Find out.
Read Guide →Tax Credits & Incentives
Complete guide to the 30% federal ITC, state rebates, SRECs, and tax exemptions. Updated for 2026.
Read Guide →Quick Answers to Common Questions
What Size Solar System Do I Need?
It depends on your energy usage. A typical off-grid cabin running lights, a fridge, laptop, and ceiling fan needs about 1.5–3 kW of solar panels and a 5–10 kWh battery bank. Use our calculator to get an accurate design for your specific needs.
How Much Does Off-Grid Solar Cost?
A complete off-grid system for a small cabin costs $8,000–$15,000. A full-time home system costs $15,000–$30,000. The 30% federal tax credit applies to all of these, reducing your net cost by thousands.
How Long Do Solar Batteries Last?
LiFePO4 batteries last 10-15 years (3,000-6,000 cycles). AGM lasts 3-5 years. Flooded lead-acid lasts 2-5 years. LiFePO4 costs more upfront but has the lowest total cost of ownership.
Powered by Trusted Data
Every calculation on SolarCalc.fyi is backed by authoritative data sources. We don't guess — we use the same data professional solar installers rely on.
See all our references on the Resources page.