There are 315 sleeps (315 days) until September 3 (Friday, September 3, 2027).
There are 315 days until September 3 (Friday, September 3, 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 3. Sleeps are the same as days.
315 sleeps is 45 weeks.