Ovulation Calculator
Enter the first day of your last period and your usual cycle length to see your likely ovulation date, fertile window and the next three cycles. A guide only, not medical advice.
Dieser Inhalt ist auf Englisch.
A guide only and not medical advice. It does not work as contraception. Speak to a GP or practice nurse if you have been trying for a baby for a year (or six months if you are over 35).
Durchgerechnete Beispiele
28 day cycle
Last period started 5 January 2027, 28 day cycle
Most likely ovulation: Tuesday, 19 January 2027 Fertile window: Thu 14 Jan to Wed 20 Jan Ovulation could fall between: Sun 17 Jan and Sat 23 Jan Next period expected: Tuesday, 2 February 2027 Cycle starts | Fertile window | Likely ovulation | Next period Tue 5 Jan | Thu 14 Jan to Wed 20 Jan | Tue 19 Jan | Tue 2 Feb Tue 2 Feb | Thu 11 Feb to Wed 17 Feb | Tue 16 Feb | Tue 2 Mar Tue 2 Mar | Thu 11 Mar to Wed 17 Mar | Tue 16 Mar | Tue 30 Mar
Ovulation falls 14 days before the next period.
32 day cycle
Last period started 5 January 2027, 32 day cycle
Most likely ovulation: Saturday, 23 January 2027 Fertile window: Mon 18 Jan to Sun 24 Jan Ovulation could fall between: Thu 21 Jan and Wed 27 Jan Next period expected: Saturday, 6 February 2027 Cycle starts | Fertile window | Likely ovulation | Next period Tue 5 Jan | Mon 18 Jan to Sun 24 Jan | Sat 23 Jan | Sat 6 Feb Sat 6 Feb | Fri 19 Feb to Thu 25 Feb | Wed 24 Feb | Wed 10 Mar Wed 10 Mar | Tue 23 Mar to Mon 29 Mar | Sun 28 Mar | Sun 11 Apr
A longer cycle moves ovulation later.
Über Ovulation Calculator
This ovulation calculator estimates when you are most likely to ovulate. Enter the first day of your last period and the usual length of your cycle. It shows your likely ovulation date, a fertile window, the wider range in which ovulation could fall and the next three cycles.
It uses the timings the NHS gives: ovulation usually happens 10 to 16 days before your next period, an egg lives for up to 24 hours and sperm can live inside the body for up to 7 days. The tool takes the middle of that range, 14 days before the next period. It is a guide, not medical advice, and it is not contraception.
So verwenden Sie Ovulation Calculator
- Enter the first day of your last period.
- Enter your usual cycle length in days.
- Read the likely ovulation date, the fertile window and the next three cycles.
Typische Einsatzzwecke
- Planning when to try for a baby
- Predicting the next period
- Seeing how a longer or shorter cycle moves ovulation
- Looking ahead over a few months
Häufige Fragen
When do you ovulate?
The NHS says ovulation usually happens 10 to 16 days before your next period starts. In a 28 day cycle that is around day 12 to 18, and the tool’s central estimate is day 14.
How long is the fertile window?
An egg lives for up to 24 hours after it is released and sperm can survive up to 7 days, so the days before ovulation matter most. The tool shows 5 days before to 1 day after the likely date.
Can I use this as contraception?
No. Cycles vary and a calendar guess is not reliable enough to prevent pregnancy.
What if my cycle is irregular?
The dates are less reliable. Ovulation tests, tracking your own signs or advice from a GP or practice nurse will help.