How do you calculate the size of a house window?

To calculate the size of a house window, measure its width and height in inches or centimeters. Multiply these two dimensions to get the area in square inches or square centimeters. If you need the size in square feet or square meters, convert the area accordingly by dividing by 144 (for square feet) or 10,000 (for square meters). Ensure to account for any framing or trim that may affect the overall dimensions.