Design Your Off-Grid Solar System
Free, fast, no signup required. Enter your appliances, pick your location, and get an initial solar and battery sizing estimate in seconds.
Start Designing →☀️ Solar planning estimates | ⏱ Takes about 2 minutes | 🔋 Panels, battery and inverter sizing
Start with an everyday use case
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. If data is unavailable, we use an estimated fallback.
Initial Equipment Sizing
Battery bank (LiFePO4, AGM, or lead-acid), solar panels, inverter, and charge controller — all sized for your specific needs.
Cost Estimates
Compare indicative equipment costs before incentives. Confirm current prices, installation costs and eligibility separately.
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, covering the basics of off-grid system planning.
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
Understand the end of the residential federal clean energy credit and where to check local incentives. 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. These are broad planning ranges, not quotes. Do not deduct a federal residential credit for new installations placed in service after December 31, 2025.
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
Our calculator combines user inputs, sizing assumptions and available solar resource data. Review the assumptions and limitations before using an estimate.
See all our references on the Resources page.
From sizing to shopping
Compare DIY solar panels and inverters by application and published specifications.
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