Next period
Dec 4 - Dec 8
Period length: 5 day(s)
Cycle intelligence
Period Calculator
Track previous cycles, mirror calculator.net-level predictions, and go deeper with fertile windows, ovulation confidence, PDF-ready summaries, and science-backed coaching notes—all in one world-class dashboard.
Updated instantly when you calculate or reset.
Peak ovulation
Dec 18, 2025
Aim to test LH surge the day prior.
Fertile window
Dec 13 - Dec 19
Best chance when intercourse happens every other day.
Full calendar outlook
Previous three months keep you honest with historical bleed patterns. The next three months mirror the data-rich layout from calculator.net—with richer color cues for period, fertile, and ovulation days.
Previous 3 months
September 2025
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PeriodFertileOvulation
October 2025
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November 2025
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Next 3 months
December 2025
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PeriodFertileOvulation
January 2026
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February 2026
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PeriodFertileOvulation
Important dates for the next 6 cycles
Aligned with medical references: period spans, ovulation dates, and fertile windows are calculated off the classic "cycle length – 14 days" rule while giving you more visual context than calculator.net.
| Cycle # | Period days | Most probable ovulation | Fertile window |
|---|---|---|---|
| 1 | Dec 4 - Dec 8 | Dec 18 | Dec 13 - Dec 19 |
| 2 | Jan 1 - Jan 5 | Jan 15 | Jan 10 - Jan 16 |
| 3 | Jan 29 - Feb 2 | Feb 12 | Feb 7 - Feb 13 |
| 4 | Feb 26 - Mar 2 | Mar 12 | Mar 7 - Mar 13 |
| 5 | Mar 26 - Mar 30 | Apr 9 | Apr 4 - Apr 10 |
| 6 | Apr 23 - Apr 27 | May 7 | May 2 - May 8 |
Cycle quick facts
- Cycle length entered: 28 days
- Average bleed length: 5 days
- Ovulation assumed 14 days before next period.
- Fertile window spans the five days before ovulation plus the day after.
Clinician-approved tips
- Track cervical mucus—egg-white texture typically lines up with the fertile window.
- Use LH surge strips around day 13 to capture peak fertility.
- Basal body temperature rises ~0.3°C after ovulation; charting confirms the pattern.
- See a clinician if cycles suddenly vary by more than 8 days from your baseline.
Menstrual cycle explained
The follicular phase prepares an egg and thickens the uterine lining. Roughly mid-cycle, a surge of luteinizing hormone triggers ovulation. If the egg is not fertilized within 24 hours, hormone levels drop and the lining is shed as a period. Only 15% of people have a textbook 28-day cycle, so using calculators like this—with inputs you control—keeps the predictions personal and clinically relevant.
This planner mirrors the information density of calculator.net and adds richer charts, instant PDF exports, and proactive reminders for the moments that matter most.