Predict your next period, ovulation date, and fertile window.
Predict your next period, ovulation date, and fertile window.
Next = LMP + Cycle Length; Ovulation = LMP + Cycle – 14
28-day cycle, LMP April 1 → Next April 29, Ovulation April 15.
Enter values above and click Calculate. All computation happens locally in your browser — no data is sent to any server.
What is Period Calculator?
Predict your next period, ovulation date, and fertile window.
Formula used?
Next = LMP + Cycle Length; Ovulation = LMP + Cycle – 14
Is it free?
Yes! All CalcNest AI tools are 100% free.
Is my data safe?
All calculations run locally. We never store or transmit your data.