Sleep Calculator
Find the best times to sleep or wake up based on sleep cycles. Select your goal and time below to optimize your rest, and learn about the stages of sleep.
Understanding Sleep Stages
Each sleep cycle (~90 minutes) includes four stages that support physical and mental health. Below, learn about each stage and its impacts.
Stage N1 (Light Sleep)
This initial stage transitions you from wakefulness to sleep. Your breathing and heart rate slow, and muscles relax. Positive: Eases you into deeper sleep, reducing stress. Negative: Easily disrupted, offering little restoration if interrupted.
Stage N2 (Light Sleep)
A deeper light sleep where body temperature drops and brain waves slow. Positive: Consolidates memories and restores energy. Negative: Interruptions can impair focus and cause daytime fatigue.
Stage N3 (Deep Sleep)
Also called slow-wave sleep, this is the most restorative stage. Your body repairs tissues and boosts immunity. Positive: Enhances physical recovery and energy. Negative: Missing this stage leads to tiredness and weakened immunity.
Stage REM (Rapid Eye Movement)
Brain activity spikes, and vivid dreams occur. Muscles are paralyzed except for eyes and breathing. Positive: Supports emotional memory, creativity, and mood. Negative: Lack of REM can cause irritability and memory issues.
Why Cycles Matter: Aim for 4-6 cycles (6-9 hours) to balance all stages. Waking at the end of a cycle (in N1/N2) feels refreshing, while incomplete cycles can leave you groggy.
Disclaimer: This sleep calculator is for informational purposes only and not a substitute for professional medical advice. Consult a healthcare provider for personalized guidance. See our Disclaimer for details.