All Solar Calculators

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

• Caravan & Motorhome Solar Calculator
  Free UK caravan solar calculator: enter daily Wh, peak sun hours and battery type — get panel wattage, leisure battery Ah, MPPT controller and inverter size for touring caravans and motorhomes.
• How Many Solar Panels Do I Need?
  Free UK calculator to estimate how many solar panels your home needs. Uses MCS-aligned irradiance, average British household consumption (2,700 kWh/yr), and 400 W panel specs.
• Solar Export Tariff (SEG) Calculator
  Calculate your annual Smart Export Guarantee revenue. Free 2026 calculator with Octopus Outgoing 15p, E.ON Next Export 16.5p, EDF SEG 5.6p, and OVO Smart Export Plus rates.
• Solar Panel Replacement Cost Calculator (UK)
  Free UK solar panel replacement cost calculator. Work out labour, materials, MCS recycling and call-out costs and compare against a full new MCS install.
• EV Charging Calculator (UK)
  Free EV charging calculator for UK drivers. Estimate kWh drawn, charge time on a 7 kW home wallbox, electricity cost at 2026 Ofgem cap rates, and the savings if you charge from solar PV.
• Hybrid Solar System Calculator
  Size a hybrid PV and battery system for UK homes: array kWp, usable battery kWh, hybrid inverter rating, and SEG export. MCS-aligned defaults.
• Off-Grid Solar System Calculator (UK)
  Free UK off-grid solar calculator. Sizes PV array (kWp), battery bank (kWh), and inverter (kW) from daily kWh load using PVGIS irradiance data and MCS-aligned design factors.
• Solar Investment Tax Credit Calculator (UK)
  Free commercial solar investment tax credit calculator for UK businesses. Estimate your Annual Investment Allowance (AIA), 50% First-Year Allowance, Smart Export Guarantee tariff, and net cost after every business incentive.
• SEG Net Export Savings Calculator (UK)
  Calculate your annual electricity bill savings under the UK Smart Export Guarantee (SEG). Compares Octopus Outgoing, E.ON Next Export, OVO, EDF and British Gas tariffs.
• Solar Panel Soiling Loss Calculator (UK)
  Estimate annual generation lost to dust, pollen and bird droppings on UK PV systems. Calculates baseline soiling, kWh recovered by cleaning, and whether a paid clean pays back at SEG export and import rates.
• Solar Panel Savings Calculator (UK)
  Free solar panel savings calculator for UK homes. Estimate 25-year lifetime savings using your annual generation, Ofgem tariff cap rate, SEG export tariff, self-consumption rate, and price escalation.
• Cost of Solar Panels Calculator (UK)
  Free UK solar panel cost calculator. Estimate installed cost from your monthly kWh, peak sun hours, £/W price, and the 0% VAT relief. 2026 MCS, Energy Saving Trust and Solar Energy UK data.
• EV Charging Cost Calculator (UK)
  UK EV charging cost calculator using April 2026 Ofgem cap rates and Octopus Intelligent Go off-peak tariffs. Per-session and annual running cost on a 7 kW wallbox plus solar PV offset.
• Solar Carport Cost Calculator
  Free UK solar carport cost calculator. Itemise steel structure, foundations, MCS-certified PV, inverter, labour, DNO fees, and EV charger costs in pounds.
• Solar Charge Controller Size Calculator
  Size a PWM or MPPT solar charge controller for any off-grid array in the UK. BS 7671 / IET Guidance Note 7 sizing, 12 V / 24 V / 48 V banks, free.
• Solar Fuse Size Calculator
  Free solar fuse size calculator for UK PV installations. Calculate gPV string fuses, battery DC fuses, and inverter protection sized to BS 7671 and IEC 60269-6.
• Solar Panel Output Calculator (UK)
  Free UK solar panel output calculator. Estimate daily, monthly, and 25-year kWh production from your array, sun hours, and system efficiency — plus pound savings.
• Solar Self-Consumption Calculator (UK)
  Free 2026 calculator for UK solar self-consumption and SEG savings. See how a 5–10 kWh battery lifts self-use from 30% to 75% under Octopus Outgoing, British Gas SEG, and post-FIT export tariffs.
• Solar Carport Calculator (UK)
  Free UK solar carport calculator. Price the steel canopy + PV + EV charger, then see annual SEG income and 25-year savings in seconds.
• Solar Generator Sizing Calculator (UK)
  Size a portable solar generator for UK camping, caravanning and power-cut backup. Calculate battery Wh, inverter W and solar panel W with UK sun-hour data.
• Solar Inverter Size Calculator (UK)
  Free UK solar inverter sizing calculator. Enter your array kWp and target DC/AC ratio to get the recommended inverter AC kW and annual clipping loss for British weather.
• Microinverter vs String Inverter Calculator
  Compare microinverter vs string inverter cost, yield, payback and 25-year ROI for UK residential solar in 2026. Enphase IQ8 vs SolarEdge HD-Wave vs SMA Sunny Boy.
• Solar Panel Tax Relief & Grant Calculator
  Free solar tax relief and grant calculator for UK homeowners. Estimate the value of 0% VAT (HMRC Notice 708/6), ECO4, HUG2, and council grants on your domestic solar installation.
• Solar Electricity Bill Savings Calculator (UK)
  Calculate how much your monthly electric bill drops after going solar in the UK. Free tool with Ofgem default tariff cap, SEG export rates, and MCS-aligned production figures.
• Solar Irradiance Calculator (GHI / DNI / DHI → POA)
  Free solar irradiance calculator for UK sites. Convert GHI / DNI / DHI to plane-of-array (POA) energy with the isotropic Liu–Jordan model. Defaults from PVGIS 5.2.
• Solar Panel Azimuth Calculator (UK)
  Calculate the precise annual production loss when your UK solar array deviates from due south. Free 2026 azimuth calculator with PVGIS-validated math, Economy 7 / Octopus Agile time-of-use split, and pound-sterling lost-generation value.
• Solar Panel Estimate Calculator
  Free solar panel estimate calculator for UK homes. System size, annual generation, gross & net cost (0% VAT), year-1 savings with Octopus Outgoing 15p export, payback and 25-year lifetime savings. 2026 MCS and Energy Saving Trust data.
• Solar Panel Fire Rating Calculator
  Free fire rating calculator for UK rooftop PV. Combines module fire type (IEC 61730) and roof covering classification (BS 476-3 / EN 13501-5 Broof) to return the system fire class and Approved Document B / BS 8579 compliance.
• Solar Panel Temperature Coefficient Calculator
  Calculate the power, voltage, and current derate your PV module sees at any cell temperature. Free 2026 calculator using the IEC 61853-2 NOCT thermal model with MCS-aligned defaults for UK climate conditions.
• Solar Pool Heating Calculator
  Size a solar pool heating system for UK climates and estimate annual savings vs gas or heat pump. Free calculator with MCS-compliant guidance and BS EN 12975 background.
• Solar Pool Pump Calculator (UK)
  Size a solar-powered pool pump and PV array for a UK swimming pool. Calculates required flow rate, pump wattage, panel size and savings vs your existing mains pump.
• Solar Battery Bank Sizing Calculator
  Free UK solar battery bank sizing calculator. Size your battery in Ah and kWh for off-grid cabins, motorhomes, or grid-tied storage based on daily load and autonomy.
• Solar Battery ROI Calculator (United Kingdom)
  Work out the 2026 payback period, 10-year NPV and ROI of a home battery in the UK. Free calculator with 0% VAT, SEG export rates, MCS-certified install costs and Ofgem price-cap data.
• Solar Greenhouse Calculator
  Calculate the PV system size and annual energy to run a heated UK greenhouse. Free calculator with MCS-grade U-values, climate degree-days, and payback.
• Solar Irrigation System Calculator
  Size a solar irrigation system for UK horticulture, polytunnels and small holdings using ETc, MCS-aligned PV data and Energy Saving Trust guidance.
• Solar Loan Calculator (UK)
  Free UK solar loan calculator. Estimate the monthly repayment, total interest, and year-1 net cash flow on a financed residential PV system using current 2026 lender APRs and Octopus SEG export pricing.
• Solar Panel Bypass Diode Calculator
  Size your PV module bypass diodes to BS EN 61730-2 and estimate annual kWh lost to substring shading on UK rooftops.
• Solar Panel Cleaning Cost Calculator (UK)
  Free UK solar panel cleaning cost calculator. Estimate per-visit, annual, and 25-year cost in pounds — and whether cleaning pays back in extra kWh.
• Solar Panel CO2 Savings Calculator (UK)
  Estimate annual and lifetime CO2 emissions avoided by your UK solar PV system, net of embodied manufacturing carbon. Free 2026 calculator using BEIS GHG Conversion Factors 2024 grid intensity and IEA PVPS Task 12 LCA data.
• Solar Panel Degradation Calculator (UK)
  Estimate UK solar panel output loss with first-year LID and annual degradation. Free calculator for 25-year cumulative kWh, MCS-aligned warranty checks.
• Solar Panel Hail Resistance Calculator
  Free hail resistance calculator for UK PV modules. Compute hailstone impact energy against IEC 61215 Class 3–5 and MCS recommendations for UK installations.
• Solar Panel Installation Angle Calculator (UK)
  Free UK solar panel installation angle calculator. Compare your roof pitch to the latitude-optimal angle for British weather, see annual yield loss, and find the wedge bracket size needed for flat-roof and shallow-pitch installs.
• Solar Panels kWh Calculator
  Free solar panels kWh calculator for the UK. Enter your monthly kWh use, target offset, and panel wattage to see system size, panel count, and bill savings — calibrated to PVGIS-SARAH3 and MCS standards.
• Solar Panel Payback Calculator (UK)
  Free solar panel payback calculator for UK homes. Estimate the year your system breaks even using your installed cost, electricity rate, Smart Export Guarantee tariff, and realistic Ofgem-tracked rate increases.
• Solar Panel ROI Calculator (UK)
  Free solar panel ROI calculator for UK households. Estimate payback, lifetime savings, and IRR using your installed cost, tariff, and SEG export rate.
• Solar Panel Roof Load Calculator
  Free solar panel roof load calculator for UK homes. Compare PV array dead load against BS EN 1991-1-1 imposed roof loads in kg/m² with MCS-aligned guidance.
• Solar Panel Snow Load Calculator
  Free UK solar panel snow load calculator. Compute characteristic and design snow loads to BS EN 1991-1-3 with per-fixing shear demand in kN/m² and N for any UK altitude.
• Solar Panel Tilt Calculator (UK)
  Free UK solar panel tilt calculator. Find the best fixed tilt for year-round, summer or winter generation across England, Scotland, Wales and Northern Ireland.
• Solar Panel Warranty Calculator
  Calculate the minimum kWh a solar panel manufacturer guarantees at year N under UK MCS-installed Tier-1 warranties. Linear and stepped curves, lifetime kWh floor.
• Solar Panel Wind Load Calculator
  Free solar panel wind load calculator for UK installs. Compute uplift on a PV array against BS EN 1991-1-4 with coach-screw withdrawal demand in N/m² and N.
• Solar Cable Size Calculator (UK)
  Free UK solar cable size calculator. Enter voltage, current, and cable run length to get the smallest copper cross-section that stays within BS 7671 voltage-drop limits.
• Solar Permit Cost Calculator (UK)
  Free UK solar permit cost calculator. Estimate DNO G98/G99 application, MCS certification, Building Control and inspection fees for domestic and commercial PV.
• Solar String Sizing Calculator
  Work out maximum and minimum solar panels per string for any inverter. BS 7671 / IEC 62548 cold-Voc and MPPT-window calculator, free.
• Solar System Efficiency Calculator (Performance Ratio — UK)
  Calculate your PV system's Performance Ratio from kWp nameplate to AC kWh delivered. Free 2026 calculator with MCS-aligned UK defaults covering temperature, soiling, mismatch, DC/AC cabling, inverter, and availability losses.
• Solar Water Pump Calculator
  Size a solar water pumping system for smallholdings, livestock troughs, or off-grid use in the UK. Free calculator with British climate data and MCS-aligned sizing.
• Agrivoltaics Yield Calculator
  Calculate combined PV and crop revenue from a UK agrivoltaic field. Free tool using Solar Energy UK data and Defra crop margins per hectare.
• Solar Panel Row Spacing Calculator
  Work out the minimum spacing between rows of tilted solar panels to avoid winter solstice self-shading on UK sites. Free 2026 calculator with MCS Domestic Installation Standard 10am–2pm solar window.
• Solar Inverter Clipping Calculator
  Estimate annual energy clipped by inverter saturation, the net value of oversizing the DC array against MCS-certified inverters, and the optimal DC/AC ratio for UK irradiance and SEG export tariffs.
• Solar Panel Charge Time Calculator (UK)
  Free UK solar panel charge time calculator. Estimate how many sun hours or days your solar array needs to recharge a leisure or off-grid battery from any depth of discharge.
• Solar Panel Monitoring ROI Calculator
  Free calculator for the payback and lifetime return of adding SolarEdge, Enphase, Tigo, or Fronius monitoring to a UK residential solar system. MCS, SEG and TOU figures.
• Solar Panel Orientation Calculator (UK)
  Free UK solar panel orientation calculator. Enter your latitude, roof azimuth and pitch — see the percentage of optimal yield versus due-south, MCS-style.
• Solar Panel Recycling Cost Calculator
  Estimate the cost of recycling decommissioned solar panels in the UK under WEEE Regulations 2013. Includes PV CYCLE UK gate fees, transport, and material-recovery rebates.
• Solar Panel Shading Calculator
  Estimate annual kWh and revenue lost to partial shading on your UK solar array. Free calculator covering bypass-diode and microinverter topologies.
• Solar Voltage Drop Calculator (UK)
  Free UK solar voltage drop calculator. Enter system voltage, current, cable length and mm² to see drop in volts and percentage. BS 7671 compliant.
• Solar String Mismatch Calculator
  Work out the power lost when solar panels of different current or wattage share one series string. First-principles I–V mismatch maths, BS 7671 aligned, free.
• Solar Thermal vs Solar PV for Hot Water (UK)
  Compare solar thermal panels vs solar PV + heat-pump cylinder for UK domestic hot water. Free calculator with MCS/Energy Saving Trust costs, BUS grant and payback.
• Solar Tracker vs Fixed-Tilt ROI Calculator
  Compare single-axis solar tracker vs fixed-tilt installed cost, annual yield, MCS SEG payback, and 25-year ROI for UK residential and small-commercial PV in 2026.
• Solar Bifacial Gain Calculator (UK)
  Estimate the rear-side bifacial gain for a UK PV array from bifaciality factor, ground albedo, mounting height and GCR — and convert it to extra kWh and pounds saved at MCS-compliant assumptions.
• Solar Panel Flood Damage Calculator
  Estimate immersion damage, expected annual loss, and 25-year cost for ground-mount and rooftop solar arrays across Environment Agency Flood Zones 1 to 3b.
• Solar PV Earthing & CPC Size Calculator (BS 7671)
  Size the circuit protective conductor (CPC) and module-frame bonding for a UK domestic PV array per BS 7671:2018+A2 Table 54.7 and MCS 005. Free copper / aluminium lookup.
• Solar Loft Fan Calculator
  Size a solar loft fan from your loft floor area and target air changes. UK calculator with Approved Document F vent area, fan wattage, and payback.
• Solar Panel Lightning Protection Calculator
  Estimate annual lightning strike probability, 25-year damage cost and the BS EN 62305 protection level required for rooftop and ground-mount solar PV in the UK.
• Solar Panel Snow Loss Calculator (UK)
  Calculate yearly energy lost to snow cover on UK solar PV by tilt, latitude and seasonal snowfall. Free calculator covering MCS-compliant installations.
• Solar Lease vs Buy Calculator (UK)
  Free UK solar lease vs buy calculator. Compare cash purchase, financed purchase, and rent-a-roof / PPA over 25 years using current 2026 zero-VAT pricing, MCS-installer rates, and Octopus SEG export tariffs.
• Solar Panel Saltwater Corrosion Calculator
  Calculate ISO 9223 corrosivity category, lifetime reduction and 25-year extra cost for solar panels installed on UK coastal properties. Based on IEC 61701 salt-mist data and MCS guidance.
• Solar Panel Soiling Loss Calculator
  Work out yearly energy lost to soiling on UK solar panels from PM2.5, pollen, and dust. Compare rain-only baseline against a paid cleaning schedule with ROI.