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Ovulation is when an ovary releases an egg, and it is the day you are most likely to conceive. This calculator estimates your ovulation date and the days around it when you are most fertile, from your last period and cycle length.
Enter the first day of your last period and your average cycle length to see your estimated ovulation date, fertile window and next expected period.
| First Day of Last Menstrual Period | 1 Jun 2026 |
| Average Cycle Length | 28 days |
| Estimated ovulation date | Mon, 2 Nov 2026 |
| Fertile window | Wed, 28 Oct 2026 – Tue, 3 Nov 2026 |
| Most fertile days | 31 Oct – 2 Nov 2026 (2 days before ovulation and ovulation day) |
| Ovulation happens on | Cycle day 15 |
| Next period expected | Mon, 16 Nov 2026 |
| Pregnancy test from | Tue, 17 Nov 2026 |
| Due date if you conceive this cycle | Mon, 26 Jul 2027 |
Ovulation Mon, 2 Nov 2026; fertile window Wed, 28 Oct 2026 – Tue, 3 Nov 2026.
Try this example →| First Day of Last Menstrual Period | 1 Jun 2026 |
| Average Cycle Length | 32 days |
| Estimated ovulation date | Sun, 25 Oct 2026 |
| Fertile window | Tue, 20 Oct 2026 – Mon, 26 Oct 2026 |
| Most fertile days | 23 Oct – 25 Oct 2026 (2 days before ovulation and ovulation day) |
| Ovulation happens on | Cycle day 19 |
| Next period expected | Sun, 8 Nov 2026 |
| Pregnancy test from | Mon, 9 Nov 2026 |
| Due date if you conceive this cycle | Sun, 18 Jul 2027 |
Ovulation Sun, 25 Oct 2026; fertile window Tue, 20 Oct 2026 – Mon, 26 Oct 2026.
Try this example →Sperm can survive in the body for up to 5 days, and the egg survives about 24 hours after release, so intercourse anytime in this window can lead to conception.
It is far less reliable for irregular cycles. Ovulation predictor kits or tracking basal body temperature give a more accurate picture.
It is typical, but the follicular phase (before ovulation) varies more than the luteal phase (after it), so the actual day can shift.
About 14 days before your next period: day 14 of a 28-day cycle, day 16 of a 30-day cycle and day 21 of a 35-day cycle.
The two days before ovulation and ovulation day itself.