Period Calculator
Predict your next period, ovulation day, and fertile window using your average cycle length.
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
Monday, March 30, 2026
Ends Friday, April 3, 2026
✨Ovulation day
Monday, March 16, 2026
Fertile window Mar 11, 2026 – Mar 17, 2026
⏱️Cycle length
28 days
5 day period
📅Projected cycles
6 upcoming
Mar 30, 2026 → Aug 17, 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 | Mar 30, 2026 – Apr 3, 2026 | Mar 16, 2026 | Mar 11, 2026 – Mar 17, 2026 | Happening now |
| Cycle 2 | Apr 27, 2026 – May 1, 2026 | Apr 13, 2026 | Apr 8, 2026 – Apr 14, 2026 | 27 days |
| Cycle 3 | May 25, 2026 – May 29, 2026 | May 11, 2026 | May 6, 2026 – May 12, 2026 | 55 days |
| Cycle 4 | Jun 22, 2026 – Jun 26, 2026 | Jun 8, 2026 | Jun 3, 2026 – Jun 9, 2026 | 83 days |
| Cycle 5 | Jul 20, 2026 – Jul 24, 2026 | Jul 6, 2026 | Jul 1, 2026 – Jul 7, 2026 | 111 days |
| Cycle 6 | Aug 17, 2026 – Aug 21, 2026 | Aug 3, 2026 | Jul 29, 2026 – Aug 4, 2026 | 139 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.