Calculate the required glass or window surface area for windows based on the dimensions of the building.
The window calculator calculates the window area, the size of the opening with the frame, and estimates energy loss based on the window’s U-value and area. Suitable for window replacement projects.
The calculator is free, works in the browser, and does not require registration. The site offers over 200 calculators with up-to-date data.
Opening = (Window width + 50 mm) × (Window height + 100 mm). Loss (W) = U-value × Area × ΔT.
Fill in your information in the fields and press the calculate button – the result will appear immediately.
Window 1,200 × 1,400 mm, U = 0.8 W/m²K, outside −20 °C, inside +21 °C → loss = 0.8 × 1.68 × 41 = 55 W.
Enter your own information into the calculator to get a personalized result.
The calculator is suitable for individuals, entrepreneurs, and professionals. All calculators on the site are free of charge.
The result is an estimate or calculated value – for official matters, verify the numbers with official sources or an expert.
Calculate the required glass or window area for windows based on the building dimensions. Fill in the requested information in the form, and the window calculator will show the result instantly.
Yes, the window calculator is completely free and does not require registration. All FiksuLaskuri construction and home calculators are free of charge.
No. The calculations are done entirely in your browser and the data you enter is not sent or stored on the server.
The window calculator provides a good starting point for purchases, often with a small margin for error. For larger projects, it's advisable to request precise measurements and quotes from a professional.
Yes – at the bottom of the page, you can see other calculators related to the same topic that may also interest you.