There are 337 sleeps (337 days) until September 25 (Saturday, September 25, 2027).
There are 337 days until September 25 (Saturday, September 25, 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 25. Sleeps are the same as days.
337 sleeps is 48 weeks and 1 sleep.