Ovulation Calculator
Find your fertile window and next ovulation date.
Ovulation Calculator
Enter your values and calculate
days
How This Calculator Works
Ovulation typically occurs 14 days before your next period. The fertile window spans about 6 days — 5 before ovulation plus the day of ovulation — since sperm survive up to 5 days.
Formula
Ovulation = LMP + cycle length − 14 days
Example
With a 28-day cycle and LMP of Jan 1, ovulation is around Jan 15, with a fertile window of Jan 10–16.
Practical Use Cases
- Family planning
- Conception timing
- Cycle tracking