Ovulation & Pregnancy Due Date Calculator

Enter the first day of your last period and your average cycle length to estimate ovulation day, fertile window, and expected due date.

Frequently Asked Questions

How does this calculator estimate ovulation?

This calculator assumes ovulation occurs roughly 'luteal length' days before the next period. By subtracting the luteal length from the cycle length and adding that to the LMP, we estimate ovulation.

What is luteal length?

The luteal phase is the time between ovulation and the next period. Average is ~14 days but varies.

Is this accurate for irregular cycles?

It is an estimate. Track multiple cycles or use fertility monitoring for better accuracy.