A method is provided herein for determining a remaining useful life of an air filter. The method includes, but is not limited to, measuring a first airflow rate and a first air pressure (P1) in an air cleaner assembly downstream of the air filter, wherein P1 corresponds to the first airflow rate. The method further includes measuring a second airflow rate and a second air pressure (P2) in the air cleaner assembly downstream of the air filter, wherein P2 corresponds to the second airflow rate. The method further includes obtaining pressure differentials A1, A2, B1, and B2 from a data storage device. The method also includes calculating with a processor a result indicative of a useful life remaining for the air filter by taking into account P1, P2, A1, A2, B1, and B2. The method also includes reporting the result to a user.