Period Tracker/Cycle Predictor
Track Your Next Period
Enter your cycle details to predict your next period, fertile window & ovulation day
Please select the first day of your last period.
The first day you had full flow
Please select your cycle length.
Day 1 of this period to day 1 of the next
Please select your period duration.
How many days your period typically lasts
Next Period
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Ovulation Day
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Fertile Window
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6-day window
Cycle Phase Today
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as of today
Your Cycle at a Glance
Month
Cycle lengths naturally vary month to month. If your cycle regularly falls outside 21–35 days, consider speaking with your healthcare provider.
How Does the Period Tracker Work?
This tracker uses the first day of your last period, your average cycle length, and your typical period duration to predict your next period, ovulation day, and fertile window with accuracy.
Ovulation is estimated 14 days before your next period — adjusted automatically if your cycle differs from 28 days. Your fertile window spans the 5 days before ovulation plus ovulation day itself, giving you a 6-day conception window.
Switch between List View for a quick breakdown of each key date, and Calendar View to see your full month colour-coded at a glance. Use the arrows to navigate to future months.
Frequently Asked Questions
Predictions are most accurate for women with regular cycles. Stress, illness, weight changes, and hormonal fluctuations can shift your period by several days. Track your actual start dates over 3+ months to improve the accuracy of your average cycle length.
Your cycle has four phases: Menstruation (your period), the Follicular Phase (period end to ovulation, when oestrogen rises), Ovulation (egg release, your peak fertility day), and the Luteal Phase (ovulation to next period, when progesterone rises).
A period a few days late is common and usually caused by stress, travel, or minor hormonal shifts. If you are sexually active and your period is more than a week late, take a pregnancy test. Consistently late or missed periods are worth discussing with your doctor.
Yes — use your average cycle length from the past 3–6 months for the most useful estimate. For highly irregular cycles, pairing this tool with BBT tracking and ovulation test strips gives you a more accurate real-time picture of your fertility.
Most periods last between 3 and 7 days, with 5 days being the average. A period consistently shorter than 2 days or longer than 8 days may be worth discussing with your healthcare provider to rule out any underlying conditions.
This tool is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider for personalised guidance.