Health · Free tool
Ovulation / Period Tracker
Predicts your fertile window using the standard luteal-phase rule (ovulation = next period − 14 days; sperm survives ~5 days, egg ~24 hours).
How it works
The tracker uses the standard luteal-phase rule: ovulation falls 14 days before the next expected period, regardless of cycle length. Sperm can survive up to 5 days in the female reproductive tract and the released egg lives ~24 hours, so the fertile window covers 5 days before ovulation through 1 day after.
Worked example
Suppose your last period started 3 May 2026 and your average cycle is 30 days. The next period is predicted around 2 June 2026; ovulation lands 14 days earlier, on 19 May 2026. The fertile window runs 14–20 May, with peak fertility on 18–19 May. Cycles vary ±3 days between months, so treat the window as a guide, not a guarantee.
When to use this
- Trying to conceive — time intercourse during the 6-day fertile window
- Tracking PCOS or irregular cycles (28–35 days is normal in Indian women)
- Planning travel, surgery or fasting around your next expected period
- Confirming pregnancy likelihood after a missed period
For deeper background on cervical-mucus signs and how stress shifts ovulation, read our guide on the fertility window. To estimate due date once pregnant, use the pregnancy due date calculator.
FAQ
Is the calendar method reliable for contraception?
No. Calendar method has ~24% failure rate as contraception. Sperm survives 5 days, ovulation timing is hard to predict precisely (especially with irregular cycles). Use barrier or hormonal methods if pregnancy avoidance is the goal.
Can I get pregnant outside the fertile window?
Less likely but not zero. Cycles vary; ovulation can come earlier/later than expected. The 6-day fertile window is statistical — not absolute.
What if my cycle is irregular (PCOS)?
Calendar prediction breaks down. Track basal body temp + LH urine sticks (e.g. Clearblue) to detect actual ovulation. For pregnancy planning with irregular cycles, see a fertility specialist.