Period Tools

What is Period Tools?

Period Tools offers a free period calculator and private cycle tracker for periods, fertility, and pregnancy planning. You can estimate your next six periods, ovulation day, and fertile window by entering the first day of your last period and your average cycle length. It runs in your browser, so your data stays on your device and nothing is saved to a server. The site also includes many related calculators and guides, covering late periods, pregnancy due dates, ovulation signs, cycle tracking, and menstrual health. It is designed to be simple, mobile-friendly, and useful for everyday planning.

Key features

• Predicts next six periods, ovulation, and fertile windows.
• Runs fully in the browser without server-side storage.
• Logs periods privately to learn your personal average.
• Includes calculators for late periods and pregnancy due dates.
• Highlights cycle phases with a clear calendar view.
• Offers guides on ovulation, cycles, and menstrual health.