Solar Panel Calculator

    Estimate daily, monthly, and yearly solar energy production.

    Auto-set from the location selector, but it can be adjusted manually.

    This can reflect inverter losses, dirt, shade, wiring, and other practical losses.

    Estimated Output

    Daily Output

    11.25 kWh

    Monthly Output

    337.50 kWh

    Yearly Output

    4106.25 kWh

    CO₂ Saved

    1713.56 kg/year

    Quick rule of thumb

    Bigger systems, stronger sun exposure, and better efficiency all increase energy output, but real roofs and local conditions can change actual results a lot.

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    Solar Output Guide

    Solar panels generate electricity through photovoltaic cells, but actual output depends on more than panel wattage alone. Sun exposure, system losses, shading, orientation, and weather all influence what a system really produces.

    Main drivers of solar production

    • Panel wattage
    • Number of panels
    • Peak sun hours
    • System efficiency
    • Roof angle, direction, and shading

    Why the CO₂ figure is only an estimate

    Carbon savings depend on what local grid electricity would otherwise have been used. Different regions have different electricity mixes, so this is best treated as a useful estimate rather than an exact result.

    Solar Panel Calculator: Estimate Energy Production from a Solar System

    This solar panel calculator estimates how much electricity a solar system could generate based on panel wattage, panel count, sunlight hours, and overall efficiency. It provides quick daily, monthly, and yearly estimates that can help with early-stage planning.

    It is useful for comparing different system sizes, checking whether a roof setup may cover part of household energy demand, and getting a rough idea of long-term energy production.


    How solar panel output is estimated

    A common estimate multiplies four main elements:

    • Panel wattage
    • Number of panels
    • Peak sun hours per day
    • System efficiency

    The basic structure is: panel power × panel count × sun hours × efficiency with the result converted into kilowatt-hours.

    This does not replace a detailed site survey, but it is a practical first-pass estimate.


    What affects real-world solar generation?

    Two systems with the same rated wattage can perform very differently in practice. Output is shaped by a mix of physical, technical, and environmental conditions.

    • Roof orientation and angle: south-facing systems in the northern hemisphere often perform better
    • Shade: trees, chimneys, nearby buildings, and seasonal shade can reduce output
    • Temperature: panels can lose efficiency in high heat
    • Inverter losses: not all generated DC power is delivered as usable AC power
    • Dirt and maintenance: dust, debris, and snow can reduce performance
    • Local climate: cloud cover and seasonal variation matter a lot

    Understanding peak sun hours

    Peak sun hours are not the same as total daylight hours. They represent the equivalent number of hours per day when sunlight intensity averages around full solar irradiance.

    That is why a location can have far more than 5 hours of daylight but still be estimated at around 5 peak sun hours for solar production purposes.


    What the calculator results mean

    • Daily output: the estimated electricity generated in a typical day
    • Monthly output: a rough 30-day estimate
    • Yearly output: a broad annual total based on daily average assumptions
    • CO₂ saved: a simplified estimate of avoided emissions compared with grid electricity

    These are planning figures rather than guaranteed outcomes.


    Typical household energy comparison

    A useful next step is to compare annual solar output with actual electricity usage. For many homes, electricity consumption varies strongly by heating system, appliances, air conditioning, and occupancy.

    • Small apartments may use far less electricity than larger detached homes
    • Homes with electric heating or EV charging often consume much more
    • Battery storage can change how much solar power is used on-site

    Financial considerations

    Energy production is only one part of a solar decision. A full appraisal usually also considers:

    • Installation cost
    • Available incentives or tax credits
    • Electricity prices
    • Export tariffs or feed-in payments where relevant
    • Maintenance expectations
    • Likely payback period

    A system with strong output may still need careful financial review, especially where roof work, batteries, or inverter replacement are part of the project.


    Common questions

    How do I calculate solar panel output?

    A simple estimate is panel wattage × number of panels × peak sun hours × system efficiency, then divide by 1,000 to convert watt-hours to kilowatt-hours.

    What are peak sun hours?

    Peak sun hours are a simplified way of expressing the amount of solar energy available in a day. They are not the same as total daylight hours.

    Why does system efficiency matter?

    Real systems lose energy through inverter inefficiency, wiring losses, dirt, shading, temperature effects, and other practical factors.

    How accurate is a solar panel calculator?

    It is useful for estimation and comparison, but actual production depends on roof angle, orientation, shade, local weather, panel type, and installation quality.

    Can solar panels cover all household electricity use?

    Sometimes, but it depends on system size, energy usage, battery storage, and local sunlight conditions.


    Related tools

    For connected calculations, see the Electrical Unit Converter, Area Converter, and Concrete Calculator.


    Final note

    This tool is most useful for quick estimates and option comparison. For a precise system design, site-specific assessment, shading review, and local production modelling are still needed.