Period Calculator
Predict your next period, ovulation day, and fertile window based on your typical cycle length
Most cycles range between 24 and 35 days.
Ovulation typically occurs 14 days before your next period.
6 cycles
🩸Next period starts
Saturday, December 6, 2025
Ends Wednesday, December 10, 2025
✨Ovulation day
Saturday, November 22, 2025
Fertile window Nov 17, 2025 – Nov 23, 2025
⏱️Cycle length
28 days
5 day period
📅Projected cycles
6 upcoming
Dec 6, 2025 → Apr 25, 2026
Upcoming cycle timeline
We project the next 6 cycles using your averages. Actual timing can shift with stress, travel, postpartum changes, or hormonal contraception.
| Cycle | Period | Ovulation | Fertile window | Days until |
|---|---|---|---|---|
| Cycle 1 | Dec 6, 2025 – Dec 10, 2025 | Nov 22, 2025 | Nov 17, 2025 – Nov 23, 2025 | Happening now |
| Cycle 2 | Jan 3, 2026 – Jan 7, 2026 | Dec 20, 2025 | Dec 15, 2025 – Dec 21, 2025 | 28 days |
| Cycle 3 | Jan 31, 2026 – Feb 4, 2026 | Jan 17, 2026 | Jan 12, 2026 – Jan 18, 2026 | 56 days |
| Cycle 4 | Feb 28, 2026 – Mar 4, 2026 | Feb 14, 2026 | Feb 9, 2026 – Feb 15, 2026 | 84 days |
| Cycle 5 | Mar 28, 2026 – Apr 1, 2026 | Mar 14, 2026 | Mar 9, 2026 – Mar 15, 2026 | 112 days |
| Cycle 6 | Apr 25, 2026 – Apr 29, 2026 | Apr 11, 2026 | Apr 6, 2026 – Apr 12, 2026 | 140 days |
Cycle insights
- • Track at least three months to refine your average cycle length.
- • Ovulation predictor kits or basal temperature tracking can confirm fertile days.
- • Stress, illness, and travel can delay ovulation or shorten the luteal phase.
Important notes
- • This tool offers estimates and is not a substitute for medical advice.
- • Irregular cycles, PCOS, postpartum recovery, or hormonal birth control may alter results.
- • See a clinician if your period is consistently very short, very long, or absent.