Tool4SaaS

Ovulation Calculator

Track ovulation and fertile window from last period and cycle length. See fertile days, due hints and calenda. 100% private and offline.

Average cycle, typically 28 days (20–45)

Enter your last menstrual period date to calculate ovulation.

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About the author

Written and maintained by the Tool4SaaS team. Every tool runs locally in your browser and is tested in-house for accuracy. Last updated: .

Frequently asked questions

Ovulation = LMP + (cycle-14); fertile window is ovulation-5 to ovulation+1.

No, for informational purposes only. Consult a healthcare professional for personal guidance. Consult a healthcare professional.

Yes, it is free, works offline in your browser, and your data never leaves your device.

How to use Ovulation Calculator

  1. Enter LMP: Pick last period date.
  2. Set cycle: Enter cycle length.
  3. View: See ovulation and fertile days.