Solar Calculators
Size your solar system with confidence. Calculate panel output, battery bank capacity, charge times, and more for off-grid and grid-tied installations.
Solar sizing has a natural order, and the wrong starting point is what trips up most builds. Step one is the daily energy budget — watt-hours per day, not panel watts. Step two is panels: how many you need to replace that budget on an average day in your latitude, accounting for tilt, shading, and 70–80% real-world efficiency against rated output. Step three is the battery bank: enough to cover your worst expected stretch of cloudy days at 50% depth-of-discharge for lead-acid or 80% for LiFePO4. Step four is the charge controller and inverter, which size off the panels and bank you've already chosen. Skip a step and you'll either undersize a critical component or pay for capacity you can't use.
The places people get stuck are predictable. Daily load math comes first — the off-grid load calculator tallies appliances by watts and hours, including the inverter overhead most spreadsheets miss. Once that number is locked, the panel size estimator converts it to a panel-array target for your latitude and sun hours. From there, the battery bank size calculator handles the autonomy days. Grid-tied owners thinking about payback should start instead with the solar ROI calculator — it accounts for utility rates, federal credits, and net-metering rules that swing break-even by years. Two more details that throw off first-time builds: panels are rated at Standard Test Conditions (25°C cell temperature, 1000 W/m² irradiance), but real-world cell temperature in summer hits 50–65°C, which cuts output another 8–15% on top of weather losses; and charge controllers clip output above their rated current, so over-paneling a 40A MPPT controller with 600W of panels at 12V is a configuration error, not a free upgrade. The calculators flag both. Every tool is browser-side and requires no sign-in.
Solar Panel Output Calculator
Calculate daily and monthly energy output from your solar panels. Enter wattage, sun hours, and panel count for instant results.
Solar Panel and Battery Sizing Calculator
Size your complete off-grid solar system. Enter daily usage, sun hours, and battery specs to get panel and battery bank recommendations.
Solar Battery Charge Time Calculator
Calculate how long your solar panels take to charge your battery bank. Accounts for sun hours, system voltage, and real-world losses.
Solar Panel Size Estimator
Estimate what size solar panel array you need based on daily energy use. Quick sizing tool for homes, RVs, and off-grid setups.
Solar Battery Bank Size Calculator
Calculate the battery bank capacity your off-grid solar system needs. Enter daily usage, autonomy days, and system voltage.
Solar Watts to Amps Calculator
Convert solar panel output from watts to amps at any system voltage. Essential for sizing wires, fuses, and charge controllers.
Solar Panel Roof Area Calculator
Calculate how many solar panels fit on your roof and the total output potential. Enter roof dimensions and panel specs.
Solar Time Calculator
Calculate apparent solar time and solar noon for any location. Enter longitude and date to find when the sun is highest.
How Many Batteries for a Solar System?
Figure out how many batteries your solar system needs for reliable off-grid power. Enter daily usage, autonomy, and battery specs.
Solar Panel Size Calculator
Calculate the right solar panel wattage and quantity for your energy needs. Compare panel sizes and find the best fit.
What Size Inverter for a 1500W Heater?
Size an inverter, battery bank, and solar array to run a 1500W space heater off-grid. Complete system sizing in one tool.
How Many Batteries for a Camper?
Calculate how many batteries your camper or van needs based on your appliance list and travel style.
Solar ROI Calculator
Calculate your solar panel payback period, 25-year savings, and return on investment. Enter system cost, size, and electricity rate.
Solar Panel Angle Calculator
Find the optimal tilt angle for your solar panels by latitude and season. Maximize energy output with the right panel angle.
Off-Grid Load Calculator
Calculate your total daily energy needs for off-grid living. Get recommended battery bank size and solar panel wattage for your system.