There are a few common window blind sizes, including 24-inch by 24-inch, 36-inch by 60-inch and 48-inch by 48-inch blinds. Custom window blinds can also be made for windows with non-standard sizes as well.
Standard sized window blinds can be purchased in many retail outlets stores and online. In order to purchase the proper size window blinds, homeowners should measure the interior of the window frame to assure an accurate fit. Both the width and length of the window opening is needed. Some window treatment companies will visit the home to measure, for an additional cost, ensuring that the blinds are a perfect fit.