By Moonlight is a characteristic parlor piano piece from the late 19th century American tradition. It relies on simple melodic ornamentation and a gently rolling accompaniment to evoke a sentimental nocturnal atmosphere.
The primary challenge is maintaining a consistent, flowing triplet pulse while balancing the melody against the moving accompaniment.
Comparable difficulty and character — good candidates for what to learn next.
By Moonlight is rated Henle level 2 of 9 — beginner repertoire, roughly ABRSM grades 2–3. In the RCM system it corresponds to about level 3.
You should be comfortable at Henle level 2 — meaning you can already play level 1–2 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of By Moonlight lasts about 3 minutes.
By Moonlight is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include Bright Eyes Polka by Thomas H. Rollinson, Albumblad, EG 109 by Edvard Grieg, Au matin by Paul Wachs — see the full similar-pieces list on this page.