Schubert's D.576 consists of thirteen variations on a theme by his friend Josef Hüttenbrenner. These variations showcase Schubert's characteristic melodic gift and his exploration of harmonic color.
Achieving a singing tone and sensitive dynamic control throughout the lyrical variations requires careful attention.
13 Variations on a Theme of Hüttenbrenner (D.576) is rated Henle level 3 of 9 — late beginner repertoire, roughly ABRSM grades 4–5. In the RCM system it corresponds to about level 4.
You should be comfortable at Henle level 3 — meaning you can already play level 2–3 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 13 Variations on a Theme of Hüttenbrenner (D.576) lasts about 10 minutes.
13 Variations on a Theme of Hüttenbrenner (D.576) is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.