There are 345 sleeps (345 days) until October 4 (Monday, October 4, 2027).
There are 345 days until October 4 (Monday, October 4, 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 October 4. Sleeps are the same as days.
345 sleeps is 49 weeks and 2 sleeps.