Solar Calculator Hub
Accurately estimate your solar panel needs, installation costs and potential savings. Plan your energy independence today — free, no signup.
Do the math before you sign
Solar quotes vary wildly. These tools give you an independent baseline — so you know a fair price when you see one.
Accurate calculations
Sizing math based on your location's peak sun hours, electricity rate and real system losses — not generic rules of thumb.
Savings estimates
Monthly and annual savings, 25-year projections with price escalation, payback period and net profit on every estimate.
Global data
Localized calculators for the USA, UK, India, Australia, Pakistan and the Philippines — local currency, rates and incentives.
Off-grid tools
Planning an RV, cabin or backup setup? Size your inverter and battery bank for the outage hours you actually need.
Tools for every solar question
Size the system, price the job, check the payback — whichever question you're asking.
Solar calculators by country
Local currency, electricity rates, sun hours and incentives — pick your country to start.
Guides, prices & explainers
Practical guides and expert advice to help you navigate the transition to renewable energy with clarity and confidence.
Independent solar math
Solar Calculator Hub is an independent resource providing transparent data for renewable energy. Our mission is to help you understand the math behind solar energy — from system sizing to ROI — so you can make an informed investment for your home or business. We don't sell panels; we just do the arithmetic.
Straight answers
How do I calculate what size solar system I need?
Divide your monthly electricity bill by your rate per kWh to get monthly usage, divide by 30 for daily kWh, then divide by your area's peak sun hours times 0.78 (system losses). A US home with a $150 bill at $0.17/kWh uses ~29 kWh/day and needs roughly a 9 kW system. The country calculators above do this math for you.
How much does a solar panel system cost in 2026?
Installed residential prices run about $2.50–$3.50 per watt in the US (a 6 kW system ≈ $15,000–$21,000 before the 30% federal tax credit), £1.20–£1.50/W in the UK, ~₹60,000/kW in India before subsidy, ~A$1.00–$1.10/W in Australia, ~Rs 140–160/W in Pakistan and ~₱70–90/W in the Philippines.
What is the payback period for home solar?
Most residential systems pay back in 4–8 years depending on electricity rates, sun hours and incentives. High-rate regions (UK, Australia, Philippines) pay back fastest. After payback, the electricity is essentially free for the remaining 15–20 years of panel life.
How many solar panels do I need?
Divide your target system size in watts by the panel wattage. A 6,000 W system with 410 W panels needs 15 panels (6,000 / 410 = 14.6, rounded up). Each panel needs about 2 m² of roof space including spacing.
Do I need batteries with solar panels?
Not necessarily. Grid-tied systems without batteries are cheapest and use net metering to credit surplus power. Add batteries if you face outages, have time-of-use rates, or want backup power — the solar system calculator sizes both the inverter and the battery bank.
How long do solar panels last?
Most panels carry a 25-year performance warranty and degrade about 0.5% per year, still producing ~87% of rated output at year 25. Inverters typically last 10–15 years; lithium batteries 10+ years.
Is solar worth it if my roof is shaded?
Heavy shading can cut output 25–50%, which stretches payback. A site survey with a shade analysis tells you the real number — if one roof face is clear, panels go there. Ground mounts are an option when the roof doesn't cooperate.
What is net metering?
Net metering credits you for surplus electricity your panels send to the grid, offsetting what you draw at night. Policies differ by country and utility — some pay full retail rate, others a lower export rate — and the terms directly affect your payback period.