Predict your next period, fertile window, and ovulation. 100% private — nothing leaves your device.
This tool runs entirely in your browser. No data is sent to any server. No cookies, no tracking. Your health data stays on your device only.
Period & Cycle Calculator is a free, browser-based tool designed for students, professionals, and anyone who needs quick calculations. Track your menstrual cycle. Predict next period, fertile window, and ovulation day. Private — no data leaves your device. Free online period calculator. Everything runs locally in your browser using JavaScript — no data is ever sent to a server, making it completely private and secure. The tool is designed to be intuitive and beginner-friendly while still offering advanced features for power users. It loads instantly with no installation required and works offline once loaded. Use it as often as you need — there are no daily limits, no watermarks, and no hidden fees.
Yes! Period & Cycle Calculator is completely free with no signup required. It runs entirely in your browser — your data never leaves your device.
Simply enter your values in the input fields above and the results update instantly. No button clicks needed — everything calculates in real-time.
Absolutely. Period & Cycle Calculator runs 100% client-side in your browser using JavaScript. No data is uploaded, stored, or shared with any server. Your privacy is guaranteed.