Period Calculator
Track your menstrual cycle and predict future periods, ovulation, and fertile windows.
Calendar Legend
Next Period Expected
Sun, Oct 4, 2026
Average cycle length (days)
28 days
Regular
Cycle Regularity
Upcoming Periods
Sun, Oct 4, 2026
Cycle 1
Sun, Nov 1, 2026
Cycle 2
Sun, Nov 29, 2026
Cycle 3
Sun, Dec 27, 2026
Cycle 4
Sun, Jan 24, 2027
Cycle 5
Sun, Feb 21, 2027
Cycle 6
Fertile Windows & Ovulation
Sep 15 - Sep 21
Ovulation: Sep 20
Cycle 1
Oct 13 - Oct 19
Ovulation: Oct 18
Cycle 2
Nov 10 - Nov 16
Ovulation: Nov 15
Cycle 3
Dec 8 - Dec 14
Ovulation: Dec 13
Cycle 4
Jan 5 - Jan 11
Ovulation: Jan 10
Cycle 5
Feb 2 - Feb 8
Ovulation: Feb 7
Cycle 6
Understanding Your Cycle
A typical menstrual cycle lasts 21-35 days. The cycle has four phases: menstruation (days 1-5), follicular phase (days 1-13), ovulation (day 14), and luteal phase (days 15-28). Tracking helps identify patterns.
Benefits of Tracking
Period tracking helps you prepare for your period, identify irregular cycles, optimize conception timing if trying to conceive, and notice health changes to discuss with your doctor.
When to See a Doctor
Consult a healthcare provider if your cycle is consistently shorter than 21 days or longer than 35 days, you miss periods, have very heavy bleeding, or experience severe pain.