This underground station has four tracks and two side platforms. The two center tracks are used by the N train on weekdays and Q train at all times except late nights. The platforms have their original trim line, which has "23" tablets on it at regular intervals and name tablets, which read "23RD STREET" in Times New Roman font. This station's 1970s overhaul included fixing its structure and the overall appearance by replacing the original wall tiles, old signs, and incandescent lighting to the 1970s modern look wall tile band and tablet mosaics, signs and fluorescent lights. It also included fixing staircases and platform edges. In 2001, the station received a major state of repairs, including upgrading for ADA compliance, restoring the original late 1910s tiling, repairing the staircases, re-tiling for the walls, new tiling on the floors, upgrading the station's lights and the public address system, installing ADA yellow safety threads along the platform edge, new signs, and new trackbeds in both directions. The 2002 artwork here is called Memories of Twenty-Third Street by Keith Godard. It consists of mosaics on the platform walls containing hats that famous people of the Flatiron District wore, including Oscar Wilde, Sarah Bernhardt, and W. E. B. Du Bois.
Exits
Each platform has two same-level fare control areas. The primary ones are at the north end. The Queens-bound platform has a bank of regular and high exit-only turnstiles, the station's full-time token booth, and four street stairs. Two go up to the northeast corner of Broadway and 23rd Street and the other two go to the southeast. The Brooklyn-bound platform has a bank of regular and high exit-only turnstile, a now defunct customer assistance booth, and two street stairs. One is connected to fare control via a passageway and goes up to the southeast corner of 23rd Street and Fifth Avenue outside the Flatiron Building while the other goes up to the northeast corner of Broadway and Fifth Avenue, near a midblock pedestrian crossing. The station's other two fare control areas are at the south end of the station. The one on the Manhattan-bound platform is unstaffed, containing High Entry-Exit Turnstiles and one staircase going up to the northeast corner of 22nd Street and Broadway. The one on the Brooklyn-bound platform is exit-only and has one staircase to the northwest corner of 22nd Street and Broadway. There is a crossunder here that was closed inthe 1990s and is now only used for station facilities.