There is a high degree of variation among home window sizes. Common window sizes will depend on where the windows are placed within the home. For example, bathroom windows are typically smaller than living room windows. It will also differ by style of home and by window manufacturer. In general, most house windows are between 24 and 30 inches wide and 48 to 72 inches tall. Always carefully measure existing windows before purchasing new or replacement windows.

Detail of blueprint of house
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Consult local building code requirements before altering window size or placement.

Traditional Window Sizing

In many homes, the top of the windows line up with the door height, which is 6 feet 8 inches, while the bottom of the windows is set 3 feet above the floor. Over the past several decades, pitched, raised and vaulted ceilings have become increasingly popular, making taller-than-normal windows an even more common and viable option. At least 10 inches must remain between the ceiling and the top of a window to allow space for headers, plates, trims and moldings. It is possible to extend windows less than 3 feet from the floor, but some additional safeguards may be necessary. For example, you must use special safety glass if windows are less than 18 inches off the ground.

Window Size and Room Use

Window size will vary depending on which room they are placed. Garage and basement windows, which are at the smallest end of the spectrum, are usually between 18 and 24 inches wide and 12 and 18 inches high. Bathroom windows are similarly small, typically 18 to 24 inches wide and 2 to 3 feet high. Bedroom widows fall between 2 and 4 feet wide and 3 and 5 feet tall. Dining rooms and living rooms usually have the most and the largest windows. The windows in these rooms are most commonly between 3 to 6 feet wide and 4 to 6 feet tall.

Proper Window Sizing Importance

Windows greatly impact the visual appearance and perception of houses. A miscalculation in size, location or type of windows can greatly diminish the outward appearance of the home as well as the indoor feel and appearance of a home. Too few windows, or windows that are undersized, can produce dim interior rooms that feel cramped. Oversized windows may produce glaring results that do not provide adequate privacy.

Stock Versus Custom Sized Windows

Many home centers offer relatively inexpensive, stock windows for nonprofessional installation. These windows generally fall within the range of standard sized window openings. However, there are some additional costs you may incur if you decide to purchase stock windows. For example, stock windows may require expensive or time-consuming drywall or masonry alterations.

Most professional installers will offer to measure your existing windows or openings free of charge. The windows will be special ordered, and initially more expensive, but they are guaranteed to fit. Tightly sealed, correctly sized windows are energy efficient.