🌸 Ovulation Calculator
Enter your last period and cycle length to get your ovulation day, fertile window and next period
Enter your last period and cycle length, then press
Calculate to see your result
🤚 If you are trying to conceive, pair this with an LH test kit or an ultrasound.
| Cycle | Period starts | Fertile window | Expected ovulation |
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Ovulation guide
How the date is worked out
The luteal phase — from ovulation to your next period — stays close to 14 days. So ovulation falls on your last period plus (cycle length − 14 days).
What is the fertile window?
Sperm can survive up to five days and an egg for 12–24 hours, so the window runs from five days before ovulation to one day after — seven days in all.
What counts as a normal cycle
The WHO puts a normal cycle at 21–35 days. Twenty-eight is only the average, so track at least three months and use your own mean.
🎙️ Say it, and it is written downLog your cycle just by saying it7-day free trial after sign-up · on-device speech recognitionSee Spicat →Ovulation calculator — your fertile window and expected ovulation day
This free tool estimates your ovulation day and fertile window from the first day of your last period and your cycle length. It is useful whether you are trying to conceive or tracking your cycle naturally.
Signs of ovulation
Around ovulation your basal body temperature rises by 0.2–0.5 ℃, cervical mucus turns clear and stretchy like egg white, and you may feel a one-sided ache low in the abdomen or tenderness in the breasts.
Source: NHS — Periods and fertility in the menstrual cycle
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