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.