There are 330 sleeps (330 days) until September 18 (Saturday, September 18, 2027).
There are 330 days until September 18 (Saturday, September 18, 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 18. Sleeps are the same as days.
330 sleeps is 47 weeks and 1 sleep.