# ProSolarCalc > Free, unbiased solar energy calculators for homeowners, DIY installers, and businesses worldwide. No email required, no data sold, no lead-generation. Every tool shows its formula and uses verified 2026 data, including country-specific subsidy and tariff rules (USA, India, Australia, Germany, Pakistan, UK, South Africa). ProSolarCalc covers solar savings & payback, system sizing, off-grid and battery design, wiring and engineering, backup power, EV charging, and country-specific subsidy/scheme calculators. Each calculator page includes an in-depth explanatory guide and FAQ. Figures for government schemes are dated references; the most volatile (US federal tax credit, California NEM 3.0, UK SEG, Pakistan NEPRA) should be re-verified against official sources. ## Sizing & savings - [Solar Savings & Payback Calculator (2026 Accurate)](https://prosolarcalc.com/calculators/solar-savings-calculator.html): Free solar savings and payback calculator. - [Solar System Size & Panel Count Calculator](https://prosolarcalc.com/calculators/solar-system-size-calculator.html): Free solar system size calculator. - [Solar Output Calculator — Daily & Yearly kWh](https://prosolarcalc.com/calculators/solar-output-calculator.html): Free solar output calculator. - [Home & Office Solar Sizing Calculator — System, Panels & Backup](https://prosolarcalc.com/calculators/home-office-solar-calculator.html): Free home and office solar sizing calculator. - [Solar Panel Comparison Calculator — Compare Two Panels Over 25 Years](https://prosolarcalc.com/calculators/solar-panel-comparison-calculator.html): Free solar panel comparison tool. - [Home Electrification Calculator — Solar + EV + Heat Pump Sizing](https://prosolarcalc.com/calculators/home-electrification-calculator.html): Free home electrification calculator. - [Solar Carbon Offset Calculator — CO₂ Avoided, Trees & Cars Equivalent](https://prosolarcalc.com/calculators/solar-carbon-offset-calculator.html): Free solar carbon offset calculator. ## Batteries, inverters & off-grid - [Off-Grid Battery Bank Sizing Calculator](https://prosolarcalc.com/calculators/battery-bank-calculator.html): Free off-grid battery bank sizing calculator. - [Battery Backup Runtime Calculator — How Long Will It Last](https://prosolarcalc.com/calculators/battery-runtime-calculator.html): Free battery backup runtime calculator. - [Off-Grid & Hybrid Solar Calculator — Array, Battery & Inverter Sizing](https://prosolarcalc.com/calculators/off-grid-solar-calculator.html): Free off-grid and hybrid solar system calculator. - [Inverter Sizing Calculator — Continuous & Surge Watts](https://prosolarcalc.com/calculators/inverter-sizing-calculator.html): Free inverter sizing calculator. - [Solar Charge Controller Sizing Calculator (MPPT & PWM)](https://prosolarcalc.com/calculators/charge-controller-calculator.html): Free solar charge controller calculator. - [Solar Load Calculator — Daily Watt-Hours & System Size from Your Appliances](https://prosolarcalc.com/calculators/solar-load-calculator.html): Free solar load calculator. ## Wiring & components - [Solar Wire & Cable Gauge Calculator (AWG & mm²)](https://prosolarcalc.com/calculators/wire-size-calculator.html): Free solar wire size calculator. - [Solar Voltage Drop Calculator (AWG & mm²)](https://prosolarcalc.com/calculators/voltage-drop-calculator.html): Free voltage drop calculator for solar and off-grid wiring. - [Series vs Parallel Wiring Calculator & Visualizer](https://prosolarcalc.com/calculators/series-parallel-calculator.html): Free series vs parallel wiring visualizer for solar panels and batteries. - [Solar Panel Tilt Angle Calculator — Optimal & Seasonal Angles by Latitude](https://prosolarcalc.com/calculators/solar-tilt-angle-calculator.html): Free solar panel tilt angle calculator. - [Solar String Sizing Calculator — Panels per String & Voltage Limits](https://prosolarcalc.com/calculators/solar-string-sizing-calculator.html): Free solar string sizing calculator. ## Backup, EV & appliances - [Generator Sizing Calculator — Running & Surge Watts](https://prosolarcalc.com/calculators/generator-sizing-calculator.html): Free generator sizing calculator. - [Generator vs Solar Battery Calculator — Backup Power Cost Comparison](https://prosolarcalc.com/calculators/generator-vs-battery-calculator.html): Free backup power comparison: standby generator vs solar + battery. - [EV Charging from Solar Calculator — Panels & Charge Time](https://prosolarcalc.com/calculators/ev-solar-charging-calculator.html): Free EV solar charging calculator. - [Pool Heater Sizing Calculator — BTU & Heat Pump](https://prosolarcalc.com/calculators/pool-heater-calculator.html): Free pool heater sizing calculator. - [Well Pump Sizing Calculator — HP, Watts & Solar](https://prosolarcalc.com/calculators/well-pump-calculator.html): Free well pump sizing calculator. - [Mini-Split & AC Sizing Calculator — BTU, Tons & Watts](https://prosolarcalc.com/calculators/mini-split-calculator.html): Free mini-split and AC sizing calculator. - [RV, Van & Boat Solar Calculator — Battery, Solar & Inverter](https://prosolarcalc.com/calculators/rv-van-solar-calculator.html): Free RV, van, boat and tiny-home solar calculator. ## Solar by country - [Solar Calculator USA 2026 — Savings, Payback & Net Metering by State](https://prosolarcalc.com/calculators/solar-calculator-usa.html): Free US solar calculator. - [NEM 3.0 Calculator — California Solar Battery Payback & Net Billing (2026)](https://prosolarcalc.com/calculators/nem-3-california-battery-calculator.html): Free NEM 3. ### USA — by state - [Solar Calculator Texas 2026](https://prosolarcalc.com/calculators/solar-calculator-texas.html): Localized rates, net metering and incentive context for Texas. - [Solar Calculator Florida 2026](https://prosolarcalc.com/calculators/solar-calculator-florida.html): Localized rates, net metering and incentive context for Florida. - [Solar Calculator Arizona 2026](https://prosolarcalc.com/calculators/solar-calculator-arizona.html): Localized rates, net metering and incentive context for Arizona. - [Solar Calculator New York 2026](https://prosolarcalc.com/calculators/solar-calculator-new-york.html): Localized rates, net metering and incentive context for New York. - [Solar Calculator New Jersey 2026](https://prosolarcalc.com/calculators/solar-calculator-new-jersey.html): Localized rates, net metering and incentive context for New Jersey. - [Solar Calculator Massachusetts 2026](https://prosolarcalc.com/calculators/solar-calculator-massachusetts.html): Localized rates, net metering and incentive context for Massachusetts. - [Solar Calculator India 2026 — PM Surya Ghar Subsidy, Cost & Savings](https://prosolarcalc.com/calculators/solar-calculator-india.html): Free India solar calculator with PM Surya Ghar Muft Bijli Yojana subsidy (₹30,000–₹78,000), system cost, monthly bill savings, EMI on the 7% government loan, and your free-electricity date. - [On-Grid Solar Calculator India 2026 — Net Metering, Subsidy & Savings](https://prosolarcalc.com/calculators/on-grid-solar-calculator-india.html): Free on-grid (grid-tied) solar calculator for India. - [Solar Loan EMI Calculator India 2026 — PM Surya Ghar Finance (SBI & Banks)](https://prosolarcalc.com/calculators/solar-loan-emi-calculator-india.html): Free solar loan EMI calculator for India. - [PM-KUSUM Solar Pump Calculator 2026 — Subsidy & Farmer Cost](https://prosolarcalc.com/calculators/kusum-solar-pump-calculator.html): Free PM-KUSUM solar pump calculator for Indian farmers. - [Commercial Solar Calculator India 2026 — ROI, Accelerated Depreciation & CAPEX vs RESCO](https://prosolarcalc.com/calculators/commercial-solar-calculator-india.html): Free commercial & industrial solar calculator for India. ### More countries - [Solar Calculator Bangladesh 2026 — Rooftop Cost, Net Metering & Payback](https://prosolarcalc.com/calculators/solar-calculator-bangladesh.html): Free Bangladesh solar calculator for 2026. Model Tk 5-13 slab tariffs, SREDA net metering, quarterly bulk-rate - [Solar Calculator Brazil 2026 — Lei 14.300, Savings & Payback](https://prosolarcalc.com/calculators/solar-calculator-brazil.html): Free solar calculator for Brazil: Lei 14.300 SCEE credits, Fio B 2026 schedule, R$/kWh tariffs, payback in 3-4 - [Solar Calculator Canada 2026 — Net Metering by Province, Costs & Payback](https://prosolarcalc.com/calculators/solar-calculator-canada.html): Free 2026 Canada solar calculator: province-by-province net metering, Greener Homes loan status, cold-climate - [Solar Calculator Italy 2026 — Ritiro Dedicato, Detrazione 50%](https://prosolarcalc.com/calculators/solar-calculator-italy.html): Free solar calculator for Italy: Scambio sul Posto closed, Ritiro Dedicato surplus prices, 50%/36% detrazione - [Solar Calculator Kenya 2026 — KPLC Savings, Net Metering & Payback](https://prosolarcalc.com/calculators/solar-calculator-kenya.html): Free Kenya solar calculator for 2026. Model KPLC bills near KSh 28/kWh, the 4 kW net-metering cap, real instal - [Solar Calculator Netherlands 2026 — Salderen Ends 2027, Savings & Payback](https://prosolarcalc.com/calculators/solar-calculator-netherlands.html): Free 2026 solar calculator for the Netherlands: salderen ends 1 Jan 2027, feed-in payments after, 0% BTW, plus - [Solar Calculator Nigeria 2026 — Cost, Savings vs Gensets & Payback](https://prosolarcalc.com/calculators/solar-calculator-nigeria.html): Free Nigeria solar calculator for 2026. Model Band A tariffs near N210/kWh, generator fuel savings, battery si - [Solar Calculator Philippines 2026 — Net Metering, Savings & Payback](https://prosolarcalc.com/calculators/solar-calculator-philippines.html): Free 2026 solar calculator for the Philippines. Estimate savings at Meralco rates near ₱13-14/kWh, ERC net met - [Solar Calculator Saudi Arabia 2026 — WERA Net Billing, Savings & Payback](https://prosolarcalc.com/calculators/solar-calculator-saudi-arabia.html): Free 2026 Saudi solar calculator. Model SEC tariffs of 18-30 halalas/kWh, WERA net billing export credits, sys - [Solar Calculator Spain 2026 — Autoconsumo, Surplus & Payback](https://prosolarcalc.com/calculators/solar-calculator-spain.html): Free solar calculator for Spain: autoconsumo savings, surplus compensation rates, IBI rebates and 5-7 year pay - [Solar Calculator UAE 2026 — Shams Dubai Net Metering, Savings & Payback](https://prosolarcalc.com/calculators/solar-calculator-uae.html): Free 2026 UAE solar calculator. Model DEWA slab tariffs of 23-38 fils/kWh, Shams Dubai net metering credits, v ### India — by state - [Solar Calculators by Indian State — directory](https://prosolarcalc.com/calculators/solar-calculator-india-states.html): All 28 states and 8 union territories, each localized. - [Solar Calculator Andaman & Nicobar 2026](https://prosolarcalc.com/calculators/solar-calculator-andaman-nicobar.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Andaman & Nicobar. - [Solar Calculator Andhra Pradesh 2026](https://prosolarcalc.com/calculators/solar-calculator-andhra-pradesh.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Andhra Pradesh. - [Solar Calculator Arunachal Pradesh 2026](https://prosolarcalc.com/calculators/solar-calculator-arunachal-pradesh.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Arunachal Pradesh. - [Solar Calculator Assam 2026](https://prosolarcalc.com/calculators/solar-calculator-assam.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Assam. - [Solar Calculator Bihar 2026](https://prosolarcalc.com/calculators/solar-calculator-bihar.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Bihar. - [Solar Calculator Chandigarh 2026](https://prosolarcalc.com/calculators/solar-calculator-chandigarh.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Chandigarh. - [Solar Calculator Chhattisgarh 2026](https://prosolarcalc.com/calculators/solar-calculator-chhattisgarh.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Chhattisgarh. - [Solar Calculator Dadra & Nagar Haveli and Daman & Diu 2026](https://prosolarcalc.com/calculators/solar-calculator-daman-diu.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Dadra & Nagar Haveli and Daman & Diu. - [Solar Calculator Delhi 2026](https://prosolarcalc.com/calculators/solar-calculator-delhi.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Delhi. - [Solar Calculator Goa 2026](https://prosolarcalc.com/calculators/solar-calculator-goa.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Goa. - [Solar Calculator Gujarat 2026](https://prosolarcalc.com/calculators/solar-calculator-gujarat.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Gujarat. - [Solar Calculator Haryana 2026](https://prosolarcalc.com/calculators/solar-calculator-haryana.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Haryana. - [Solar Calculator Himachal Pradesh 2026](https://prosolarcalc.com/calculators/solar-calculator-himachal-pradesh.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Himachal Pradesh. - [Solar Calculator Jammu & Kashmir 2026](https://prosolarcalc.com/calculators/solar-calculator-jammu-kashmir.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Jammu & Kashmir. - [Solar Calculator Jharkhand 2026](https://prosolarcalc.com/calculators/solar-calculator-jharkhand.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Jharkhand. - [Solar Calculator Karnataka 2026](https://prosolarcalc.com/calculators/solar-calculator-karnataka.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Karnataka. - [Solar Calculator Kerala 2026](https://prosolarcalc.com/calculators/solar-calculator-kerala.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Kerala. - [Solar Calculator Ladakh 2026](https://prosolarcalc.com/calculators/solar-calculator-ladakh.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Ladakh. - [Solar Calculator Lakshadweep 2026](https://prosolarcalc.com/calculators/solar-calculator-lakshadweep.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Lakshadweep. - [Solar Calculator Madhya Pradesh 2026](https://prosolarcalc.com/calculators/solar-calculator-madhya-pradesh.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Madhya Pradesh. - [Solar Calculator Maharashtra 2026](https://prosolarcalc.com/calculators/solar-calculator-maharashtra.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Maharashtra. - [Solar Calculator Manipur 2026](https://prosolarcalc.com/calculators/solar-calculator-manipur.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Manipur. - [Solar Calculator Meghalaya 2026](https://prosolarcalc.com/calculators/solar-calculator-meghalaya.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Meghalaya. - [Solar Calculator Mizoram 2026](https://prosolarcalc.com/calculators/solar-calculator-mizoram.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Mizoram. - [Solar Calculator Nagaland 2026](https://prosolarcalc.com/calculators/solar-calculator-nagaland.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Nagaland. - [Solar Calculator Odisha 2026](https://prosolarcalc.com/calculators/solar-calculator-odisha.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Odisha. - [Solar Calculator Puducherry 2026](https://prosolarcalc.com/calculators/solar-calculator-puducherry.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Puducherry. - [Solar Calculator Punjab 2026](https://prosolarcalc.com/calculators/solar-calculator-punjab.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Punjab. - [Solar Calculator Rajasthan 2026](https://prosolarcalc.com/calculators/solar-calculator-rajasthan.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Rajasthan. - [Solar Calculator Sikkim 2026](https://prosolarcalc.com/calculators/solar-calculator-sikkim.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Sikkim. - [Solar Calculator Tamil Nadu 2026](https://prosolarcalc.com/calculators/solar-calculator-tamil-nadu.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Tamil Nadu. - [Solar Calculator Telangana 2026](https://prosolarcalc.com/calculators/solar-calculator-telangana.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Telangana. - [Solar Calculator Tripura 2026](https://prosolarcalc.com/calculators/solar-calculator-tripura.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Tripura. - [Solar Calculator Uttar Pradesh 2026](https://prosolarcalc.com/calculators/solar-calculator-uttar-pradesh.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Uttar Pradesh. - [Solar Calculator Uttarakhand 2026](https://prosolarcalc.com/calculators/solar-calculator-uttarakhand.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for Uttarakhand. - [Solar Calculator West Bengal 2026](https://prosolarcalc.com/calculators/solar-calculator-west-bengal.html): Localized PM Surya Ghar subsidy, tariff and net-metering estimate for West Bengal. - [STC Rebate Calculator Australia 2026 — Solar & Battery Savings](https://prosolarcalc.com/calculators/solar-calculator-australia.html): Free Australian STC solar rebate calculator. - [Photovoltaik Calculator Germany 2026 — Einspeisevergütung & Eigenverbrauch](https://prosolarcalc.com/calculators/solar-calculator-germany.html): Free Germany solar (Photovoltaik) calculator. - [Solar Calculator Pakistan 2026 — Net Billing, Savings & Payback (NEPRA)](https://prosolarcalc.com/calculators/solar-calculator-pakistan.html): Free solar calculator for Pakistan. - [NEPRA Prosumer Regulations 2026 Calculator — Net Billing Bill Estimator (SRO 251)](https://prosolarcalc.com/calculators/nepra-net-billing-calculator-pakistan.html): Free calculator for Pakistan's NEPRA Prosumer Regulations 2026 (SRO 251(I)/2026, sometimes mis-cited as SRO 547). - [Solar Calculator UK 2026 — Smart Export Guarantee (SEG) Savings & Payback](https://prosolarcalc.com/calculators/solar-calculator-uk.html): Free UK solar calculator. - [Solar Calculator South Africa 2026 — Savings, Payback & Load-Shedding Backup](https://prosolarcalc.com/calculators/solar-calculator-south-africa.html): Free South Africa solar calculator. - [Solar Panels for Air Conditioner Calculator](https://prosolarcalc.com/calculators/solar-ac-calculator.html): How many panels to run a 1/1.5/2-ton AC, with night battery. - [Roof Area to Solar Panels Calculator](https://prosolarcalc.com/calculators/roof-area-solar-calculator.html): Panels that fit your roof, kW capacity and generation. - [Home Battery Payback Calculator](https://prosolarcalc.com/calculators/battery-payback-calculator.html): Is a solar battery worth it — annual value, payback, honest verdict. - [Diesel Generator vs Solar Cost Calculator](https://prosolarcalc.com/calculators/diesel-vs-solar-calculator.html): True diesel cost per kWh vs a solar hybrid, with payback. - [Solar Water Heater vs PV Calculator](https://prosolarcalc.com/calculators/solar-water-heater-calculator.html): Thermal SWH vs extra PV for hot water — savings and payback. ## Unit converters - [Watts to Amps Calculator (W to A) — DC & AC](https://prosolarcalc.com/calculators/watts-to-amps-calculator.html): Convert power to current for DC, AC single- and three-phase. - [kW to kVA Calculator](https://prosolarcalc.com/calculators/kw-to-kva-calculator.html): Real to apparent power using power factor, with kVAR. - [Ah to kWh Calculator](https://prosolarcalc.com/calculators/ah-to-kwh-calculator.html): Battery amp-hours to kilowatt-hours by voltage, plus usable capacity. - [AWG to mm² Calculator](https://prosolarcalc.com/calculators/awg-to-mm2-calculator.html): Wire gauge conversion with diameter and typical ampacity. - [BTU to kW Calculator](https://prosolarcalc.com/calculators/btu-to-kw-calculator.html): Cooling/heating capacity between BTU/hr, kW, tons and watts. - [kWh to MJ Calculator](https://prosolarcalc.com/calculators/kwh-to-mj-calculator.html): Energy units — kWh, MJ, BTU, therms, kcal. - [HP to kW Calculator](https://prosolarcalc.com/calculators/hp-to-kw-calculator.html): Horsepower to kilowatts and watts for motors and pumps. - [Ohm’s Law Calculator](https://prosolarcalc.com/calculators/ohms-law-calculator.html): Solve volts, amps, ohms and watts from any two. ## Guides & site - [How Much Electricity Does a Solar Panel Produce?](https://prosolarcalc.com/guides/how-much-electricity-does-a-solar-panel-produce.html): How much electricity a solar panel really produces: the daily kWh formula, peak sun hours by climate, every lo - [Solar Panel Efficiency: What the Numbers Mean](https://prosolarcalc.com/guides/solar-panel-efficiency-explained.html): Solar panel efficiency explained honestly: what 20-23% really means, why efficiency buys roof space rather tha - [How Many Solar Panels Do I Need? (2026 Sizing Guide)](https://prosolarcalc.com/guides/how-many-solar-panels-do-i-need.html): A clear, honest guide to working out how many solar panels you need — from your kWh usage, sun-hours and panel - [Solar Payback Period Explained: How to Calculate It Honestly (2026)](https://prosolarcalc.com/guides/solar-payback-period-explained.html): What a solar payback period really is, how to calculate it step by step, what a good payback looks like, and t - [What Size Inverter Do I Need?](https://prosolarcalc.com/guides/what-size-inverter-do-i-need.html): How to size a solar inverter: grid-tied DC/AC ratios of 1.1-1.3, off-grid load sizing at continuous watts x 1. - [Financing Solar in India, Honestly](https://prosolarcalc.com/guides/solar-loan-emi-india-guide.html): Solar loans in India for 2026: the PM Surya Ghar ~7% collateral-free loan, honest EMI maths with worked exampl - [UK Smart Export Guarantee: Rates & How It Works](https://prosolarcalc.com/guides/uk-smart-export-guarantee-guide.html): How the UK Smart Export Guarantee works in 2026: real SEG rates from about 1p to 30p/kWh, eligibility, how to - [Solar in India: The 2026 Buyer’s Guide](https://prosolarcalc.com/guides/solar-in-india-buyers-guide.html): From bill to commissioning: size your system, use the PM Surya Ghar subsidy, pick DCR panels and vendors, clea - [On-Grid vs Off-Grid vs Hybrid Solar (India)](https://prosolarcalc.com/guides/on-grid-off-grid-hybrid-india.html): On-grid, off-grid and hybrid solar compared for India: cost per kW, PM Surya Ghar eligibility, power-cut behav - [PM-KUSUM Solar Pump Guide for Farmers](https://prosolarcalc.com/guides/pm-kusum-solar-pump-guide.html): PM-KUSUM explained for farmers: Components A, B and C, subsidy shares, eligible pump sizes, diesel-vs-solar pa - [Australia's STC Rebate, Explained](https://prosolarcalc.com/guides/australia-stc-rebate-guide.html): How Australia's STC solar rebate works in 2026: the certificate formula, zone ratings, a 6.6 kW worked example - [Solar in Germany: EEG & Eigenverbrauch](https://prosolarcalc.com/guides/solar-in-germany-eeg-guide.html): How Germany's EEG feed-in tariff works in 2026: current rates and 20-year lock, why self-used solar is worth 4 - [Solar in the USA: The State-by-State Reality](https://prosolarcalc.com/guides/solar-in-usa-state-guide.html): Why US solar payback now depends on your state: electricity rates, net-metering regimes and surviving 2026 inc - [Solar Wire & Cable Sizing Guide](https://prosolarcalc.com/guides/solar-wire-cable-sizing-guide.html): Size solar wires with confidence: the NEC 1.56x ampacity rule, heat and conduit derates, the 3% voltage drop t - [Voltage Drop in Solar Systems](https://prosolarcalc.com/guides/voltage-drop-in-solar-systems.html): What voltage drop really is, the VD = 2LIR/1000 formula lever by lever, the 3% rule, a 12 V vs 48 V worked exa - [Wiring Solar Panels: Series vs Parallel](https://prosolarcalc.com/guides/series-vs-parallel-solar-wiring.html): Series adds voltage, parallel adds current. See how each wiring choice changes wire size, shading losses, fusi - [Solar Panel Tilt Angle & Orientation](https://prosolarcalc.com/guides/solar-panel-tilt-angle-orientation.html): Tilt near your latitude, face true south or north, and learn what flat, east-west or off-angle roofs really co - [Sizing an Off-Grid Battery Bank](https://prosolarcalc.com/guides/sizing-off-grid-battery-bank.html): Size an off-grid battery bank with the honest four-step method: audited daily load, days of autonomy, depth of - [String Sizing & Inverter Matching](https://prosolarcalc.com/guides/solar-string-sizing-inverter-matching.html): How to size solar strings: cold-corrected Voc against max input voltage, MPPT window checks, current limits wi - [RV, Van & Boat Solar: The Complete Guide](https://prosolarcalc.com/guides/rv-van-boat-solar-guide.html): Mobile solar plays by different rules: flat-mount losses, constant shade, DC-DC charging and LiFePO4. Honest s - [Do Solar Panels Work in Winter & Cloudy Weather?](https://prosolarcalc.com/guides/do-solar-panels-work-in-winter-cloudy-weather.html): Yes, but with less output. Honest numbers on solar in winter and cloud: 10-25% cloudy-day output, why cold helps efficie - [Is a Solar Battery Worth It? An Honest Answer](https://prosolarcalc.com/guides/is-a-solar-battery-worth-it.html): Does a home battery pay for itself? The one number that decides it, the honest payback arithmetic, and where storage gen - [Is Solar Worth It? An Honest Framework](https://prosolarcalc.com/guides/is-solar-worth-it.html): There is no universal yes or no. 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