The standard bass range bottoms out around E2, about 82 Hz, and plenty of composers stop there. Basso profondo roles go further: Osmin in Mozart's The Abduction from the Seraglio holds a long low D2 (73 Hz) near the end of his aria "Ha, wie will ich triumphieren", and Sarastro in The Magic Flute dips to about F2.
Russian choral music goes deeper still. In the fifth movement of Rachmaninoff's All-Night Vigil, the basses descend a slow scale to Bb1, about 58 Hz, a note only some singers can sound clearly. Recordings of even lower sounds exist, mostly in vocal fry, but they are stunts rather than usable singing range.
For an untrained bass, a steady F2 or E2 is an excellent bottom, and a clear D2 is rare. Bass voices also tend to mature late, often deepening and gaining power into a singer's thirties, so a young singer who reaches only G2 today may find more later. To measure only your bottom note, use the lowest note test.