Understand sleep readiness without wearing another device

Enter planned lights-out and a realistic sleep opportunity to calculate a planned wake time. This is clock arithmetic—not a sleep-cycle or sleep-stage prediction.

Calculate diary-based sleep efficiency from estimated total sleep time and time in bed, then interpret the number as a pattern—not a diagnosis or treatment target.

Explore morning, intermediate, or evening timing tendencies from free-day sleep and alertness patterns without treating a short quiz as a diagnosis or fixed identity.

Estimate the difference between your sleep need and recent sleep duration.

Work backward from bedtime by a chosen caffeine buffer so the assumption is visible and easy to adjust.

Work backward from a required wake time, sleep-opportunity goal, and wind-down allowance to plan when the routine should begin.

Organize sleep opportunity, schedule, symptoms, medication, and safety context into a clearer next question without diagnosing the cause of fatigue.

Combine recent sleep, caffeine timing, and perceived stress into a simple planning prompt without a wearable or overnight recording.

Compare sleep opportunity with a rough 90-minute cycle model while making clear that real sleep cycles vary through the night and between people.

Build a transparent planning score from recent sleep, caffeine buffer, stress, and wind-down readiness without pretending to measure sleep stages.

Choose a conservative nap plan from current sleepiness, available time, bedtime proximity, and safety context.