Likely ovulation date
Enter the first day of your last period and your cycle length.
- Fertile window11/05/2026 to 11/10/2026
- Likely ovulation11/10/2026
- Next period11/24/2026
- Ovulation on 12/08/2026period around Dec 22
- Ovulation on 01/05/2027period around Jan 19
- Ovulation on 02/02/2027period around Feb 16
How ovulation is estimated
The phase after ovulation is the steadiest part of the cycle and lasts about 14 days. The phase before, from the first day of the period to ovulation, is the one that changes from person to person. For that reason the math counts back from the next period.
The fertile window and the next few cycles are on the fertile window calculator. To predict the start of the next period, use the period calculator.
How to confirm you ovulated
| Sign or method | What shows up | Notes |
|---|---|---|
| LH test (urine) | Surge of luteinizing hormone | Ovulation usually follows 24 to 36 hours later |
| Cervical mucus | Turns clear and stretchy near ovulation | Medications and infections can change the pattern |
| Basal body temperature | Rises about 0.4 to 0.9 °F (0.2 to 0.5 °C) after ovulation | Confirms ovulation after it has happened |
| Serial ultrasound | Tracks the follicle | Done with a doctor's order |
Late ovulation and irregular cycles
Stress, illness, weight changes, breastfeeding, or polycystic ovary syndrome (PCOS) can push ovulation later. When ovulation slips, the period slips too, and the calculated date stops being accurate. An LH test or a visit with a doctor gives more reliable answers.
- Irregular cycle: enter your shortest and longest cycle on the fertile window calculator.
- Late period: try the late period calculator.
- Trying to conceive for 12 months without luck (6 months if you are 35 or older)? Ask a doctor for an evaluation.
Frequently asked questions
How do I calculate when I ovulate?
Subtract 14 from your cycle length, then count that many days from the first day of your period. In a 28-day cycle, ovulation falls on day 14. In a 30-day cycle, day 16.
How many days after my period do I ovulate?
In a 28-day cycle, ovulation comes about 14 days after the first day of your period, or 9 days after a 5-day period ends. Longer cycles mean a longer wait.
How long does ovulation last?
The egg survives 12 to 24 hours after release. The fertile window is longer, about 6 days, because sperm can live up to 5 days.
What is late ovulation?
Late ovulation means the egg is released after the usual day for the cycle, which stretches the cycle and delays the period. Stress, illness, and PCOS are common causes. A gynecologist can sort out the reason.
Are drugstore ovulation tests reliable?
They detect the LH surge, which comes 24 to 36 hours before ovulation, and work well for many people with regular cycles. With conditions like PCOS, a test can read positive without ovulation.
Can you get pregnant without ovulating?
No. Without a released egg there is nothing to fertilize. Because the exact ovulation day is uncertain, a cycle calculation should never replace birth control.
Sources and review
- American College of Obstetricians and Gynecologists (ACOG): Fertility Awareness-Based Methods of Family Planning.
- Wilcox AJ, Weinberg CR, Baird DD. Timing of sexual intercourse in relation to ovulation. New England Journal of Medicine, 1995.