Period Calculator
Track and predict your menstrual cycle, ovulation, and fertile window
Disclaimer: This calculator provides estimates based on average cycle patterns. Every person's cycle is different. This tool should not be used as a contraceptive method or for medical diagnosis. Consult a healthcare provider for personalized advice.
Your Cycle Information
Typical range: 21-35 days
Typical range: 2-8 days
Next Period
Expected Start
Fri, Jan 9, 2026
Today
Fertile Window
Sun - Sat
6 day window
Ovulation Day
Fri, Jan 23, 2026
In 14 days
Cycle Predictions
| Cycle | Period | Fertile Window | Ovulation |
|---|---|---|---|
| #1 | Fri - Tue | Sun - Sat | Fri, Jan 23, 2026 |
| #2 | Fri - Tue | Sun - Sat | Fri, Feb 20, 2026 |
| #3 | Fri - Tue | Sun - Sat | Fri, Mar 20, 2026 |
Understanding Your Cycle
Menstruation
Period days
Fertile Window
High fertility days
Ovulation
Peak fertility
Menstrual Phase: The first day of your period marks day 1 of your cycle.
Follicular Phase: Your body prepares for ovulation after menstruation ends.
Ovulation: An egg is released, typically around day 14 of a 28-day cycle.
Luteal Phase: The time between ovulation and your next period.
Tips for Tracking
- - Track your periods for at least 3-6 months to identify patterns
- - Note any symptoms like cramps, mood changes, or spotting
- - Irregular cycles can be influenced by stress, diet, exercise, and health conditions
- - Consult a doctor if your cycle is consistently shorter than 21 days or longer than 35 days
- - Use multiple methods if tracking fertility for conception or contraception