WASHINGTON — Drivers who pay metered parking with their smartphone will need to use a different app in Alexandria, Virginia, beginning Sept. 1, the city announced Thursday.

The city is change from Pango to Parkmobile, it announced.

Customers who use ParkMobile will pay the same $1.75 hourly rate as they would at pay stations and meters that accept credit cards. A 45-cent convenience fee, however, will be added.

Users must first download the free app (available for iOS and Android) and create an account.

Each time they park, app users can choose the zone number printed on parking signs and pay stations. (The app also shows zone numbers on a map, and suggests the closest zones for easy selection.)

Drivers can choose the amount of time to purchase, up to the posted time limit for the parking location. If a customer leaves the spot before the selected amount of time expires, the parking session can be stopped early, and only the time used will be charged.

Arlington County, Virginia, and D.C. are already using ParkMobile for metered parking payments, as are Montgomery and Prince George’s counties in Maryland.

Alexandria’s current pay-by-phone vendor, Pango, won’t be available after Aug. 31.