Solar Yield Calculator
Estimate the annual solar yield of your PV system based on region, orientation and roof tilt angle, entirely in your browser.
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How to use this tool (video)
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Solar yield calculator: how much power your system produces
How much electricity will a photovoltaic system actually generate at your location? Our yield calculator estimates the annual solar output of your planned or existing PV system. It accounts for the specific yield of your region in Germany, the orientation of the roof, the roof tilt and shading. The result shows your annual output in kWh, the specific yield per kWp, the CO2 savings and the share of your own household consumption. With just a few entries you know whether your roof is worth it for a system and roughly how large it should be.
How the yield estimate works
The basis is the specific yield of a well-oriented system in your region. Across Germany it averages about 965 to 1,000 kWh per kWp per year, and depending on the state the range runs from roughly 900 kWh in the north to about 1,150 kWh in the sunnier south. The calculator multiplies this value by the system size and adjusts it: a south-facing roof delivers full output, east or west roofs still about 90 percent of that, north-facing or facade systems considerably less. A flat or steep tilt and shading from trees or neighbouring buildings also reduce output.
What does "specific yield" mean?
The specific yield is the energy produced per installed capacity, that is kWh per kWp. It is the key figure for comparing sites and systems fairly, because it puts generation in relation to system size. A specific yield of 1,000 kWh/kWp means: an 8 kWp system produces around 8,000 kWh per year. This value also lets you estimate how much of your consumption the system covers and how large the savings are. Behind it always sit real losses: heat, inverter, cabling and soiling cost a few percent, usually summed up in a performance ratio of about 75 to 85 percent.
Sample calculation
An 8 kWp system in southern Germany, south-facing, 35 degrees tilt and no shading produces around 8,400 kWh per year. With an electricity consumption of 4,200 kWh it covers the entire demand more than twice over. The annual CO2 saving is about 2.9 tonnes. If you shift some consumption to midday or add a battery, the share of self-used power rises and so does the saving, because each kilowatt-hour you use yourself spares you the rate you would otherwise pay your supplier.
Frequently asked questions
How much electricity does a PV system generate per year in Germany?
A well-oriented system typically generates 950 to 1,100 kWh per kWp per year. An 8 kWp system therefore produces 7,600 to 8,800 kWh annually. The exact value depends on region, orientation, tilt and shading.
Which orientation is best?
South is most productive in Germany. East and west still deliver about 90 percent of that and spread generation better over the day, which is often advantageous for self-consumption. North-facing or facade systems produce considerably less.
What does the specific yield in kWh/kWp mean?
It shows how much energy one kWp of installed capacity produces per year. With it you can compare systems or sites fairly and scale up the output of a planned system.
How much does shading reduce output?
Even single shadow lines can lower output noticeably, because shaded module strings slow generation. The calculator applies a 5 to 20 percent reduction depending on the degree of shading.
Is this a binding yield forecast?
No. It is an estimate based on typical German yields. Real output depends on weather, site details and system quality. For binding planning, commission an installer or a solar yield study.
Are my data stored?
No. All calculations run 100 % locally in your browser. Your entries are neither sent to a server nor stored.
Read more about this tool
How the calculator works
The calculator works in a few transparent steps. From your postcode it identifies the region and applies a typical specific yield in kWh per kWp per year. It multiplies this base value by the system size in kWp that you enter. It then corrects the result with factors for orientation, roof tilt and shading: a south-facing roof at optimum tilt delivers full output, east and west about ten percent less, while steeper or flatter roofs and shade reduce it further. From the estimated annual output in kWh it then derives the specific yield, the CO2 saving and the share of your household demand.
What drives the real yield
The key factor is global irradiation, the solar energy that reaches a given surface at your location. It varies across Germany from just over 1,000 kWh per square metre in the north to around 1,200 kWh in the sunnier south. The module converts only part of this into electricity: modern panels reach efficiencies of about 20 to 22 percent. On top of that come real-world losses that professionals summarise as the performance ratio, usually 75 to 85 percent. These include heat, which makes cells less efficient at high temperatures, inverter and cabling losses, plus soiling and degradation over the years. The calculator reflects these relationships through regional averages and the location factors.
Why typical values instead of a guarantee
A reliable forecast needs many years of weather data and a site-specific shading analysis. Our calculator therefore deliberately uses published averages and gives you a well-founded order of magnitude for initial planning, not a guarantee. For a binding statement, have a specialist installer prepare a precise yield study or a satellite-based forecast.
Your data stays on your device
One more decisive point: the entire calculation runs 100 percent locally in your browser, directly on your device. Your postcode, system size and the other entries are neither sent to a server nor stored, not even by us. You can use the calculator freely even for rough planning, without any concerns about data protection.