Sleep Calculator - Calculate sleep cycles, rem & wake up time

Hi Product Hunt! 👋 I’m excited to share Sleep Calculator — a simple, ad-free tool that helps you wake up feeling more refreshed by aligning your sleep with natural 90-minute cycles. 🛌 You can: Enter your desired wake-up time, and it tells you the best time to fall asleep. Or enter your bedtime, and it tells you when to set your alarm. 🌙 Why I made it: Like many people, I often woke up groggy even after “enough” hours of sleep. After reading about 90-minute sleep cycles and REM timing, I wanted a tool that makes it easy to plan sleep and wake times. So I built this minimalist calculator — fast, mobile-friendly, and free to use (no login, no tracking, no fluff). 🚀 I'd love your feedback! Would you find a reminder feature useful? Should I turn this into a mobile app? Anything missing that could improve your sleep planning? Thanks for checking it out and sweet dreams! 😴