There are 333 sleeps (333 days) until September 21 (Tuesday, September 21, 2027).
There are 333 days until September 21 (Tuesday, September 21, 2027) — one sleep per night.
One sleep per night between now and the big day — tonight is the first sleep, and the morning after the last sleep is September 21. Sleeps are the same as days.
333 sleeps is 47 weeks and 4 sleeps.