Free Solar Calculators
150+ calculators for panels, batteries, inverters, wiring, and ROI. Instant results, no signup.
Residential Solar
Size your home solar system — panels, production, and roof fit.
☀ Solar Panel Calculator
How many panels does your home need? Enter your bill, get your answer.
🏠 How Many Solar Panels Do I Need
The #1 question. Your electricity bill in — panel count out.
⚡ Solar System Size Calculator
Calculate the right kW system size for your home.
🌞 Peak Sun Hours Calculator
Find peak sun hours for your location. The key to accurate sizing.
📐 Solar Panel Angle Calculator
Optimal tilt angle for maximum energy production year-round.
🔌 Solar Power Calculator
How much power will your solar array actually produce?
📊 Solar Panel Comparison
Compare two panels side-by-side: 25-year production, cost per kWh, and value winner.
🏛 Ground Mount Solar Calculator
Calculate land area, row spacing, and cost for ground-mounted solar arrays.
🏗 Solar Roof Load Calculator
Check if your roof can support the weight of solar panels and snow.
📐 Row Spacing Calculator
Calculate minimum panel row spacing to prevent inter-row shading.
🌡 Temperature Coefficient Calculator
See how heat reduces your panel output month by month.
🏠 Solar Pergola Calculator
Size a solar pergola: panels that fit, power output, and shade area.
❄ Snow Load & Winter Calculator
Assess snow weight on panels and estimate winter production losses.
📈 Panel Degradation Calculator
Project your panel output decline over 25 years.
Battery & Storage
Size your battery bank for backup, off-grid, or self-consumption.
🔋 Solar Battery Calculator
What battery size do you need? Based on your loads and backup hours.
⚡ Battery Bank Size Calculator
Calculate amp-hours and watt-hours for your battery bank.
🔧 Battery Sizing Calculator
Lead-acid vs lithium — the right capacity for your system.
🌐 Tesla Powerwall Calculator
How many Powerwalls for your home? Based on daily usage.
⏱ Battery Runtime Calculator
How long will your battery last under load?
⏻ Battery Charge Time Calculator
How long to charge your battery bank from solar?
Inverters & Controllers
Size inverters and charge controllers for your solar system.
🔄 Solar Inverter Size Calculator
What inverter wattage for your loads? Don't forget surge.
⚙ Charge Controller Calculator
MPPT or PWM? Calculate the right amp rating.
🔌 Inverter Sizing Calculator
Match your inverter to your peak and continuous loads.
🔗 String Sizing Calculator
Panels in series vs parallel — voltage and current optimization.
Wiring & Electrical
Wire sizing, voltage drop, fuses, and electrical safety.
🔌 Solar Wire Size Calculator
AWG or mm² — pick the right wire gauge for your solar run.
⚡ Voltage Drop Calculator
Keep voltage loss under 3%. Calculate it before you wire.
🔸 Amps Calculator
Watts to amps, amps to watts. The conversion you always need.
Ω Ohm's Law Calculator
V = IR. Calculate voltage, current, resistance, and power.
Off-Grid Systems
Complete off-grid system sizing for cabins, tiny homes, and remote sites.
🏔 Off-Grid Solar Calculator
Complete system sizing: panels, batteries, inverter, controller.
🏡 Cabin Solar Calculator
Weekend cabin or full-time? Size your off-grid system.
🏠 Tiny House Solar Calculator
Tiny house, big energy needs. Get the math right.
🔋 Solar Generator Calculator
Portable power station sizing for camping and emergencies.
🔄 Solar vs Generator
Side-by-side 20-year cost comparison of solar vs fuel generators.
🚘 Solar Carport Calculator
Size a solar carport: panels, power, EV miles, and cost.
RV, Van & Boat
Mobile solar systems for RVs, campervans, and boats.
🚌 RV Solar Calculator
How much solar for your RV? Based on your actual appliances.
🚐 Van Life Solar Calculator
Van build solar sizing — roof space, loads, and battery.
⛵ Boat Solar Calculator
Marine solar system sizing with unique boat considerations.
❄ RV AC on Solar Calculator
Can you run air conditioning on solar? Let's do the math.
Financial & ROI
Solar costs, savings, payback period, and tax credits.
💰 Solar Panel Cost Calculator
Estimate total cost for your solar installation.
📈 Solar Savings Calculator
How much will solar save you over 25 years?
📊 Solar ROI Calculator
Return on investment — is solar worth it for you?
📅 Solar Payback Calculator
How many years until solar pays for itself?
⚡ Electricity Cost Calculator
What does your electricity actually cost per kWh?
🏷 Solar Tax Credit Calculator
Calculate your federal ITC solar tax credit.
🏠 Solar Home Value Calculator
Estimate how much solar panels increase your property value.
🔄 Self-Consumption Calculator
Optimize the ratio of solar energy used on-site vs exported.
📋 Solar PPA Calculator
Compare a Power Purchase Agreement to buying or staying on the grid.
💰 Community Solar Calculator
Calculate savings from community solar subscriptions for renters.
🔊 Panel Cleaning ROI
Is professional solar panel cleaning worth the cost?
Energy Consumption
Understand your energy usage before sizing your solar system.
🎁 Appliance Energy Calculator
How much energy does each appliance use? Add them up.
⚡ kWh Calculator
Convert watts and hours to kilowatt-hours.
🔌 Power Consumption Calculator
Total power draw of your home or system.
🚘 EV Charging Calculator
How much solar to charge your electric vehicle?
🏠 Solar for Refrigerator
How many panels to run your fridge on solar.
💧 Solar Hot Tub Calculator
Size a solar system to power your hot tub.
⚙ Solar Bitcoin Mining
Calculate solar system size and savings for crypto mining.
Environmental Impact
Calculate the environmental benefits of going solar.
🌱 Solar Carbon Offset Calculator
How much CO2 does your solar system offset?
🍃 CO2 Savings Calculator
Your solar panels prevent this much carbon emissions.
🌲 Trees Equivalent Calculator
Your solar system = this many trees planted.
🌬 Solar vs Wind
Compare solar panels to wind turbines for your home.
🌾 Agrivoltaics Calculator
Dual-use farming: combine solar panels with crop production.
Tools & Converters
Quick electrical conversions and unit tools.
View all tools & converters calculators →Country-Specific
Solar calculators tailored to your country's incentives, rates, and regulations.
🇺🇸 United States
ITC tax credit, net metering by state, cost by state.
🇦🇺 Australia
Solar rebates, feed-in tariffs, high-insolation sizing.
🇬🇧 United Kingdom
SEG payments, solar grants, UK-specific panel sizing.
🇿🇦 South Africa
Load shedding backup, hybrid inverter sizing, Eskom rates.
🇨🇦 Canada
Provincial incentives, cold-climate optimization.