Actual dimensions are 20.75 x 20.25 x 5.25. Accumulair brand 20x20x5 Westinghouse MU2020 replacement whole house air filters, exactly built to substitute for the name brand Westinghouse MU2020 air filters. Completely constructed with no forming or combs needed. MERV graded to ASHRAE 52.2 test grades assuring function equal to the name brand Westinghouse MU2020 air filter. Notice: The example air filter pic displayed is not to scale and is shown for style purposes. Brand names and Westinghouse MU2020 identifier are used for filter style identification only.