Pre-solved bedtimes for an 8:00 AM wake-up based on complete 90-minute sleep cycles. Go to sleep at 12:16 AM (5 cycles, 7h 30m) or 10:46 PM (6 cycles, 9h) to wake at 8:00 AM feeling refreshed.
TO WAKE AT 8:00 AM — GO TO SLEEP AT
Includes 14 min to fall asleep · 90 min per cycle · NSF adult recommendation: 5–6 cycles (7.5–9h)
ALL BEDTIMES FOR 08:00 WAKE-UP
| Bedtime | Cycles | Duration | Quality | Note |
|---|---|---|---|---|
| 6:16 AM | 1 | 1h 30m | Insufficient | Severely sleep deprived |
| 4:46 AM | 2 | 3h | Insufficient | Severely inadequate |
| 3:16 AM | 3 | 4h 30m | Insufficient | Significantly below minimum |
| 1:46 AM | 4 | 6h | Below min | Below adult minimum |
| 12:16 AM | 5 | 7h 30m | Recommended | Minimum recommended for most adults |
| 10:46 PM | 6 | 9h | Recommended | Ideal — well-rested, full recovery |
| 9:16 PM | 7 | 10h 30m | Optional | More than most adults need |
SELECTED: 5 CYCLES · 7h 30m
12:16 AM
Minimum recommended for most adults
WAKE UP
8:00 AM
TOTAL SLEEP
7h 30m
CYCLES
5 / 6
SLEEP STAGES IN 5 CYCLES (7h 30m)
Transition to sleep, easy to wake
Core sleep, most of the night
Restorative — growth hormone, tissue repair
Memory consolidation, dreaming
Each bedtime is calculated by counting backwards from 8:00 AM in complete 90-minute sleep cycles, then subtracting 14 minutes for the average time it takes to fall asleep.
SLEEP CYCLE
90 min
N1→N2→N3→REM
SLEEP ONSET
14 min
Average to fall asleep
RECOMMENDED
5-6 cycles
7.5-9 hours (NSF adults)
Example (5 cycles): 8:00 AM − (5 × 90 min) − 14 min = 8:00 AM − 464 min = 12:16 AM
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Pre-solved bedtimes for 8:00 AM wake-up · Formula: wake − (cycles × 90 min) − 14 min · NSF adult recommendation: 7–9 hours