SleepCycle – Sleep Calculator

🌙 Wake Up at the Perfect Moment

SleepCycle uses sleep cycle science to calculate your ideal bedtime or wake-up time. By waking at the end of a sleep cycle — rather than in the middle — you avoid grogginess and start every day feeling truly rested.

### ⏰ Two Simple Modes

- Wake Up mode — Tell us when you need to get up. We'll show you the best bedtimes, from the earliest to the latest, so you can pick what fits your evening.
- Bedtime mode — Tell us when you plan to go to sleep. We'll calculate the optimal wake-up times that align with your natural sleep cycles.
- Now mode — Going to bed right now? We'll instantly show your best wake-up times based on the current time.

### 🔬 The Science Behind It

Each sleep cycle lasts approximately 90 minutes. A full night of sleep consists of 4–6 complete cycles. Waking up at the end of a cycle — during your lightest sleep phase — leaves you feeling alert and energized, while waking mid-cycle causes that familiar "groggy" feeling known as sleep inertia.

SleepCycle calculates backwards (for bedtimes) or forwards (for wake-up times) using your personalized settings, so every recommendation is tailored to you.

### ⚙️ Fully Customizable

- Adjust the time it takes you to fall asleep (5–30 minutes)
- Set your average sleep cycle length (60–120 minutes)
- Choose how many cycles to display
- All preferences are saved automatically

### 🎨 Beautiful & Personal

- Three theme modes — Light, Dark, or Follow System
- Clean, gradient-driven design that's easy on the eyes
- Minimal interface — no clutter, just what you need
- Works perfectly with Android's Material You dynamic theming

### 🌍 Multi-Language Support

SleepCycle speaks your language. Fully localized into English, 中文, Español, Français, Deutsch, 日本語, 한국어, Português, Русский, العربية, and हिन्दी.

### 🔒 Privacy First

No accounts required. Your sleep data stays on your device, always. We use anonymous analytics to improve the app — learn more in our Privacy Policy.

### ✅ What You Get

- Instant sleep cycle calculations
- Recommended cycle highlighted for each scenario
- Bedtime and wake-up time suggestions
- Customizable sleep parameters
- Clean, beautiful dark and light themes
- Eleven language options
- Anonymous usage analytics to improve the app experience

SleepCycle helps you work with your body's natural rhythm — not against it.