Free Solar Calculators & Sizing Tools

Solar Energy Calculators Made Simple

Accurately estimate your solar panel array size, battery storage capacity, ROI payback period, and monthly bill savings — 100% free with instant browser-based formulas.

Solar Tools Directory

Comprehensive Solar Calculators

Engineered with standard solar formulas to estimate system size, ROI, battery capacity, cable loss, and environmental impact.

Sizing Live Tool

Solar Panel Size Calculator

Calculate how many solar panels you need based on daily energy consumption (kWh) and peak sun hours.

Technical

Solar Energy Production Calculator

Estimate monthly and annual kWh generation using tilt, azimuth, peak sun hours, and system derate factors.

Sizing

Solar Panel Roof Space Calculator

Calculate physical roof square footage (sq ft & m²) needed for a given solar system size.

Technical

Solar Panel Wattage Calculator

Convert Standard Test Conditions (STC) panel wattage into PTC and real-world operating power.

Technical

Optimal Solar Tilt & Orientation

Find optimal solar panel tilt angle and compass orientation based on your exact latitude.

Technical

Solar Panel Temperature Loss Calculator

Calculate power degradation percentage during extreme summer heat based on temperature coefficients.

Technical

Solar Shading & Derate Factor Calculator

Estimate annual energy production loss caused by partial tree shading, soiling, and snow.

Technical

Bifacial Solar Gain Calculator

Compute extra energy yield (10%-30%) generated by rear-side reflection based on ground albedo.

Financial

Solar ROI & Payback Calculator

Estimate return on investment, break-even payback period (years), and 25-year NPV cash flow.

Financial

Solar Electricity Savings Calculator

Project your monthly and 25-year cumulative utility bill savings after switching to solar power.

Financial

Solar Installation Cost Estimator

Calculate total system cost, $/Watt market rates, Federal Tax Credit, and net out-of-pocket price.

Financial 30% Credit

Solar Federal Tax Credit (ITC) Calculator

Calculate eligible 30% Federal Investment Tax Credit dollar amount under IRS Code Section 25D.

Financial

Solar Loan & Financing EMI Calculator

Calculate monthly loan payments, dealer origination fees, interest costs, and net monthly cashflow.

Financial

Solar Lease vs Buy Comparison Calculator

Compare 25-year financial returns, tax credit ownership, and home resale value between buying and leasing.

Financial

Solar PPA Savings Calculator

Project monthly expenses under a Solar Power Purchase Agreement with annual rate escalators.

Financial

Solar Property Value Increase Calculator

Estimate real estate equity added by owned solar panels based on NBER & LBNL market studies.

Financial

Solar SREC Revenue Calculator

Calculate annual cash income earned by selling Solar Renewable Energy Certificates in active state markets.

Financial

Net Metering Credit Calculator

Calculate credits for excess energy exported to grid under NEM 2.0 vs NEM 3.0 net billing.

Battery Popular

Solar Battery Storage Sizing Calculator

Determine required battery storage capacity (kWh) for emergency outages or Time-of-Use peak shaving.

Battery

Battery Backup Run Time Calculator

Calculate how many hours or days a home battery will power essential loads during blackouts.

Battery

Battery C-Rate & Peak Discharge Calculator

Convert battery capacity (Ah/kWh) and C-rate into maximum continuous and peak surge kW output.

Battery

Battery Time-of-Use (TOU) Arbitrage

Calculate annual bill savings from charging batteries off-peak and discharging during expensive peak hours.

Battery

Battery Depth of Discharge (DoD) Calculator

Compare usable capacity vs cycle life between LiFePO4 Lithium (80-90% DoD) and Lead-Acid (50% DoD).

Battery

Off-Grid Battery Bank Voltage Calculator

Size 12V, 24V, or 48V battery banks and calculate series/parallel battery wiring configurations.

Battery

Solar Generator Sizing Calculator

Size portable power stations (EcoFlow, Jackery, Bluetti) and calculate solar recharge time.

Technical

Solar Inverter Sizing Calculator

Calculate optimal AC inverter wattage based on array DC capacity and target DC/AC ratio.

Technical

MPPT Charge Controller Calculator

Size MPPT controller voltage and amperage ratings with cold-weather Voc temperature correction.

Technical

Solar String Sizing Calculator

Calculate min and max panels per string to stay within inverter MPPT voltage windows.

Technical

Microinverter vs String Inverter Calculator

Compare equipment cost, labor, shading harvest advantage (+5-12%), and 25-year reliability.

Technical

Solar Inverter Efficiency Calculator

Calculate AC output power and conversion heat losses using CEC Weighted Efficiency metrics.

Technical

Solar Hybrid Inverter Calculator

Size hybrid inverters for simultaneous solar, battery bank, grid, and generator integration.

Technical

Solar DC Cable Size Calculator

Calculate minimum AWG or mm² DC wire gauge to keep string voltage drop under 2% (NEC 690.8).

Technical

Solar AC Output Wire Sizing Calculator

Size AC output conductors from inverter to main panel with 125% continuous duty rating.

Technical

Solar Combiner Box & Fuse Calculator

Determine string fuse requirements (NEC 690.9) and parallel array busbar ratings.

Technical NEC Code

Solar Main Panel 120% Rule Calculator

Check if your electrical main panel can accept a solar backfeed breaker (NEC 705.12).

Technical

Solar Grounding & Wire Size Calculator

Size Equipment Grounding Conductors (EGC) and GEC wires for solar modules and racking.

Technical

Solar Rapid Shutdown Compliance Calculator

Verify array compliance with NEC 690.12 firefighter 30-second rapid shutdown voltage rules.

Technical

Solar Voc Temperature Correction Calculator

Calculate max cold-weather open circuit voltage to prevent exceeding NEC 600V/1000V limits.

Off-Grid Advanced

Off-Grid Solar System Sizing Calculator

Complete suite for sizing panels, battery storage, MPPT, and generator for off-grid homes.

Off-Grid

RV & Campervan Solar Calculator

Calculate solar panels, lithium Ah battery bank, and DC-DC alternator charging for campervans.

Off-Grid

Marine & Boat Solar System Calculator

Size flexible or rigid solar panels, MPPT, and house batteries for sailboats and yachts.

Off-Grid

Solar Powered Well Pump Calculator

Calculate solar panel wattage and VFD controller for deep submersible well water pumps.

Off-Grid

Solar Shed & Workshop Calculator

Size compact solar kits for backyard sheds, workshops, man caves, and tiny cabins.

Off-Grid

Solar Panel Charging Time Calculator

Calculate exact hours needed to charge any battery capacity using solar panels.

Sizing

Solar Water Heater Sizing Calculator

Calculate collector area and storage tank size for solar thermal domestic hot water systems.

Sizing

Solar Pool Heating Collector Calculator

Calculate solar pool collector panel surface area and water temperature rise.

Sizing

Solar Air Heating Collector Calculator

Estimate room space heating BTU output and fuel savings from solar thermal air collectors.

Sizing EV Special

Solar Panels for EV Charging Calculator

Calculate how many additional solar panels are required to power an Electric Vehicle 100% on sunshine.

Technical

Solar + EV Level 2 Charger Matching

Match real-time solar generation (kW) with smart EV charger amperage (16A-48A) without grid draw.

Battery

Bidirectional EV (V2H) Home Backup Calculator

Calculate how many days an Electric Vehicle battery can power a home when paired with solar panels.

Environmental

Solar Carbon Footprint Offset Calculator

Calculate metric tons of CO2 avoided, trees planted equivalent, and EPA environmental impact metrics.

Environmental

Solar Heat Pump Energy Calculator

Size solar arrays to offset 100% of electric heat pump heating and cooling consumption.

Commercial

Commercial Solar Peak Demand Shaving

Calculate utility demand charge savings ($/kW) using commercial solar + battery energy storage.

Commercial

Solar Farm Land Area & Acreage Calculator

Calculate required land area in Acres/Hectares for utility-scale solar farms (MW capacity).

Commercial

Solar Performance Ratio (PR) Calculator

Compute official System Performance Ratio (PR %) and Capacity Factor using IEC 61724 metrics.

Commercial

Levelized Cost of Energy (LCOE) Solar Calculator

Calculate lifetime levelized cost of solar electricity ($/kWh or $/MWh) over 25-30 years.

Commercial

Ground Mount Solar Foundation Calculator

Calculate ballast block weight and driven pier post depth based on ASCE 7 wind load specs.

Utility CA Special

California NEM 3.0 Solar + Battery Calculator

Calculate solar + battery payback under California CPUC Net Billing avoided cost export rates.

Utility

Texas Free Nights Battery Arbitrage Calculator

Calculate monthly savings in Texas ERCOT market by charging batteries for free at night.

Utility

Florida Net Metering & Hurricane Backup

Calculate FPL 1:1 net metering savings combined with hurricane outage battery backup duration.

Technical

Solar Panel 25-Year Degradation Estimator

Model year-by-year output degradation over 25 years based on panel tech (PERC, TOPCon, HJT).

Technical

Solar Panel Soiling & Cleaning ROI Calculator

Calculate annual revenue lost to dust/soiling and determine if professional cleaning pays for itself.

Technical

Solar Inverter Replacement Cost Calculator

Estimate replacement cost and timing (Years 10-15) over a 25-year system lifecycle.

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