All Solar Calculators

Free tools for solar panel sizing, tilt, voltage, wiring and cost.

This directory shows only calculators whose interface, formula, worked example, sources and limitations have been reviewed together. Unreviewed topics and translations are not published or included in the sitemap.

• RV Solar Calculator
  Estimate RV panel wattage, battery Ah, controller current, and inverter capacity from explicit energy, reserve, sun, and load inputs.
• Solar Panel Tax Credit Calculator
  Model verified state, utility, legacy and business solar incentives after the homeowner Section 25D credit ended for post-2025 expenditures.
• Hybrid Solar System Calculator
  Size a grid-tied hybrid solar system: PV array kW, battery kWh, hybrid inverter capacity, and annual self-consumption. Free calculator with US defaults.
• Solar Investment Tax Credit Calculator
  Estimate your Section 48E ITC, MACRS depreciation, and bonus adders. Free solar investment tax credit calculator for U.S. commercial and business buyers.
• How Many Solar Panels Do I Need?
  Find how many solar panels you need from your monthly kWh, site solar resource, panel wattage, and an explicit performance factor.
• Off-Grid Solar System Calculator
  Size your off-grid solar system in seconds. Calculate PV array kW, battery kWh, and inverter capacity from daily load with NREL peak-sun data.
• Solar Fuse Size Calculator
  Size DC fuses for any PV string, battery bank or inverter. Free solar fuse size calculator using Isc and continuous-current NEC 690.9 rules.
• Solar Panel Replacement Cost Calculator
  Price a per-panel or full-array swap. Free solar panel replacement cost calculator covering labor, materials, recycling and full-system reinstall.
• EV Charging Cost Calculator (United States)
  Calculate wall energy, charge time, and per-session EV charging cost from battery size, state of charge, charger power, tariff, losses, and solar share.
• Solar Irradiance Calculator (GHI / DNI / DHI → POA)
  Convert GHI, DNI and DHI to plane-of-array energy. Free solar irradiance calculator using the Liu-Jordan model and NREL NSRDB state defaults.
• Solar Panel Wind Load Calculator
  Compute uplift pressure on a tilted PV array per ASCE 7-22. Free solar panel wind load calculator with anchor withdrawal demand in psf and lbf.
• Solar Carport Cost Calculator
  Price a 2026 solar carport by itemising steel, foundations, PV, inverter, labour, permits, EV charging and verified incentives.
• EV Charging Calculator
  Estimate EV charging time, kWh drawn, electricity cost, and rooftop solar savings. Free EV charging calculator using current 2026 U.S. utility rates.
• Solar Charge Controller Size Calculator
  Size a PWM or MPPT solar charge controller for any off-grid array. NEC 690.8 125% safety factor, free, 12 V / 24 V / 48 V batteries.
• Solar Feed-in Tariff Calculator (U.S. Net Metering)
  Estimate your annual solar export revenue. Free solar feed-in tariff calculator covering NEM 1.0 retail credit and NEM 3.0 avoided-cost rules.
• Solar Generator Sizing Calculator
  Estimate portable power-station battery Wh, inverter W, and solar input W from load, runtime, autonomy, losses, surge, and peak sun hours.
• Solar Loan Calculator
  Estimate monthly payment, total interest, and year-1 cash flow on a financed solar system. Free solar loan calculator using current 2026 U.S. lender APRs.
• Net Metering Savings Calculator (U.S.)
  Estimate annual bill savings under U.S. net metering. Free net metering savings calculator covering NEM 1.0 retail credit and NEM 3.0 avoided-cost.
• Solar Panel Snow Load Calculator
  Compute flat- and sloped-roof snow loads with per-anchor shear demand. Free solar panel snow load calculator built on ASCE 7-22 ground snow values.
• Solar Pool Heating Calculator
  Compare selected collector area, representative-day heat demand and solar fraction, plus an explicitly simplified annual bill and payback scenario.
• Solar Pool Pump Calculator
  Size a solar-powered pool pump and array. Calculates required flow, pump wattage, panel size, and dollar savings vs your existing 120 V / 240 V pool pump.
• Solar Panel Dust & Soiling Loss Calculator
  Estimate energy lost to dust, pollen and bird droppings on your PV array. Free solar panel soiling calculator with paid-cleaning ROI built in.
• Solar Panels kWh Calculator
  Size a solar system straight from your power bill. Free solar panels kWh calculator with system size, panel count, and savings, calibrated to NREL PVWatts.
• Solar Panel Tilt Calculator
  Calculate a latitude-based fixed-panel tilt rule of thumb for year-round, summer, or winter scenarios, with formulas and limitations.
• Solar Panel Hail Resistance Calculator
  Compute hailstone impact energy by diameter and tilt. Free solar panel hail resistance calculator scored against IEC 61215 and UL 2218 ratings.
• Solar Panel Output Calculator
  Estimate daily, monthly, annual, and forward 25-year solar output from explicit array, resource, performance, age, and rate assumptions.
• Solar Battery Bank Sizing Calculator
  Free solar battery bank sizing calculator. Size your battery bank in amp-hours and kWh based on daily load, days of autonomy, system voltage, and chemistry.
• Solar Electricity Bill Savings Calculator
  Estimate your monthly solar bill savings instantly. Free calculator with 2026 EIA retail rates, NEM 1.0/2.0/3.0 logic, and self-consumption defaults.
• Solar Inverter Size Calculator
  Convert PV array DC kW and a chosen DC/AC ratio into inverter AC kW, with a transparent heuristic clipping estimate and design limitations.
• Microinverter vs String Inverter Calculator
  Compare editable inverter-side cost and simplified shade-value scenarios for microinverters and string inverters, with exact formulas and limitations.
• Solar Panel Azimuth Calculator
  Calculate annual production loss when your array tilts off true south. Free solar panel azimuth calculator with PVWatts-validated hourly math.
• Solar Permit Cost Calculator
  Estimate building permit, plan review, interconnection and inspection fees with our free solar permit cost calculator — by AHJ, for 2026 US projects.
• Solar Self-Consumption Calculator (U.S.)
  Calculate self-consumption with and without a battery. Free solar self consumption calculator showing how Powerwall or LFP shifts NEM 3.0 savings.
• Solar Water Pump Calculator
  Size a solar water pumping system for livestock, irrigation, or off-grid use. Free calculator with US sun-hour data and NREL/USDA-derived math.
• Solar Panel Fire Rating Calculator
  Find your rooftop PV system fire class from module UL 61730 type and roof UL 790 class. Free solar panel fire rating calculator (IBC 2024).
• Cost of Solar Panels Calculator
  Estimate U.S. residential solar size and installed cost from electricity use, sun hours, quote price, and a separately verified incentive.
• Solar Panel Row Spacing Calculator
  Calculate minimum row spacing for tilted PV arrays and avoid winter self-shading. Free solar panel row spacing calculator with GCR output.
• Solar Battery ROI Calculator (U.S.)
  Estimate payback and 10-year NPV for a home battery from import rates, export compensation, cycling losses, degradation and only verified current incentives.
• Solar Carport Calculator
  Free U.S. solar carport calculator. Size the canopy, price the steel structure + PV + EV charger, and see annual savings and 25-year net benefit in seconds.
• Solar Greenhouse Calculator
  Calculate the PV system size and annual energy needed to run a heated greenhouse. Free calculator covering glazing U-values, climate zones, and payback.
• Solar Panel Installation Angle Calculator
  Compare your roof pitch to the latitude-optimal angle. Free solar panel installation angle calculator showing production loss and wedge bracket size needed.
• Solar Panel Savings Calculator
  Project your 25-year lifetime savings year-by-year. Free solar panel savings calculator with retail rate, net-metering credit, and rate escalation built in.
• Solar String Sizing Calculator
  Calculate the maximum and minimum number of solar panels per string for any inverter. NEC 690.7 cold-Voc and MPPT-window math, free.
• Solar Irrigation System Calculator
  Size a solar-powered irrigation system from crop water demand, ET, head and sun hours. Free calculator with FAO-56 method and USDA NRCS sizing rules.
• Solar Panel Bypass Diode Calculator
  Pick the right bypass-diode current and reverse-voltage rating for your PV module, and estimate annual kWh lost when shade engages the diodes.
• Solar Panel Charge Time Calculator
  Free solar panel charge time calculator. Find out how many sun hours or days your solar array needs to recharge your battery from any depth of discharge.
• Solar Panel CO2 Savings Calculator
  Estimate annual and 25-year CO2 emissions avoided by your PV system. Free solar panel CO2 savings calculator using EPA eGRID 2024 grid factors.
• Solar System Efficiency Calculator (Performance Ratio)
  Compute your PV system Performance Ratio from STC nameplate to AC delivered. Free solar system efficiency calculator with NREL-aligned loss defaults.
• Solar Tracker vs Fixed-Tilt ROI Calculator
  Compare single-axis tracker vs fixed-tilt installed cost, annual yield boost, payback, and 25-year ROI for US residential and small-commercial solar in 2026.
• Solar Bifacial Gain Calculator
  Estimate rear-side bifacial gain from bifaciality factor, albedo, mount height, and GCR — convert to extra kWh and 25-year dollar value, 2026 figures.
• Solar Panel Cleaning Cost Calculator
  Free solar panel cleaning cost calculator. Estimate per-visit, annual, and 25-year cost — and whether cleaning pays for itself in extra output.
• Solar Panel Degradation Calculator
  Estimate solar panel output loss year-by-year with first-year LID and annual degradation. Free calculator for 25-year cumulative kWh and warranty checks.
• Solar Panel Estimate Calculator
  Estimate 2026 solar system size, installed cost, payback and 25-year savings using current EnergySage and EIA benchmarks.
• Solar Panel Temperature Coefficient Calculator
  Estimate Pmax, Voc and Isc loss at any cell temperature. Free solar panel temperature coefficient calculator using the IEC 61853-2 NOCT model.
• Solar Panel Warranty Calculator
  Free calculator for the minimum power a solar panel manufacturer guarantees at year N. Linear and stepped warranty curves, lifetime kWh and revenue floor.
• Solar Panel Wire Size Calculator
  Free solar panel wire size calculator. Enter voltage, current, and run length to get the smallest AWG that stays under your max voltage drop.
• Solar Inverter Clipping Calculator
  Estimate annual energy lost to inverter clipping and find the right DC/AC ratio. Free solar inverter clipping calculator with per-PSH economics.
• Solar Panel ROI Calculator
  Estimate solar payback, lifetime savings and IRR from your installed cost, electricity rate and only the current incentives you can verify.
• Solar Panel Roof Load Calculator
  Free solar panel roof load calculator. Compare added dead load from a PV array against IBC residential roof minimums in lb/ft² with code references.
• Solar Panel Soiling Loss Calculator
  Calculate annual energy lost to soiling from PM2.5, dust, and pollen. Compare rain-only baseline against a paid cleaning schedule, with cleaning ROI.
• Solar Voltage Drop Calculator
  Free solar voltage drop calculator. Enter system voltage, current, wire length, and AWG to see drop in volts and percentage. NEC compliant.
• Solar String Mismatch Calculator
  Calculate the power lost when solar panels of different current or wattage are wired in one series string. First-principles I–V mismatch math, free.
• Solar Lease vs. Buy Calculator
  Compare cash, loan, and lease/PPA over 25 years using the actual cash price, APR, lease escalator, ownership terms and only verified current incentives.
• Solar Panel Flood Damage Calculator
  Estimate flood damage and 25-year cost for PV arrays in FEMA NFIP zones. Free solar panel flood damage calculator for ground and rooftop systems.
• Solar Panel Orientation Calculator
  Find your roof's annual production loss versus true south with our free solar panel orientation calculator using your latitude, azimuth and tilt angle.
• Solar Panel Payback Calculator
  Estimate when a solar system breaks even from installed cost, verified incentives, electricity rate, degradation and annual rate escalation.
• Solar Panel Shading Calculator
  Estimate annual kWh and revenue lost to partial shading on your solar array. Free calculator with bypass-diode and microinverter topology models.
• Solar Panel Snow Loss Calculator
  Calculate yearly solar energy lost to snow cover by latitude, tilt, and snowfall. Free calculator using the Marion 2013 NREL snow-loss model.
• Agrivoltaics Yield Calculator
  Calculate combined solar and crop revenue from an agrivoltaic field. Free calculator with NREL InSPIRE shade-tolerance factors and Land Equivalent Ratio.
• Solar Attic Fan Calculator
  Size a solar attic fan from your attic square footage and target air changes per hour. Free calculator with NFVA, fan wattage, and payback math.
• Solar Panel Grounding & EGC Size Calculator (NEC)
  Size the EGC and module-frame bonding jumper per NEC 250.122 / 690.45. Free solar panel grounding calculator with copper and aluminum lookup.
• Solar Panel Lightning Protection Calculator
  Calculate annual lightning strike probability, 25-year damage cost, and the recommended IEC 62305 protection level for rooftop and ground-mount solar systems.
• Solar Panel Monitoring ROI Calculator
  Estimate payback on adding Enphase, SolarEdge, Tigo or Fronius monitoring. Free solar panel monitoring ROI calculator with fault and soiling alerts.
• Solar Thermal vs Solar PV for Hot Water
  Compare solar thermal with PV plus a heat-pump water heater using US planning costs, energy rates, verified incentives, payback and lifetime value.
• Solar Panel Recycling Cost Calculator
  Estimate the cost to recycle decommissioned solar panels in the US. Free solar panel recycling cost calculator with gate fees and landfill compare.
• Solar Panel Saltwater Corrosion Calculator
  Estimate lifetime and 25-year extra cost for coastal PV arrays. Free solar panel saltwater corrosion calculator using ISO 9223 and IEC 61701.