Ovulation Calculator

Ovulation typically occurs 14 days before your next period. For a 28-day cycle: ovulation on day 14. For a 30-day cycle: day 16. For a 26-day cycle: day 12. The calculator shows your fertile window based on your cycle length and last period date.

The fertile window is approximately 6 days: 5 days before ovulation plus ovulation day. Sperm can survive up to 5 days in the reproductive tract. The egg is viable for 12-24 hours after release. Peak fertility is 1-2 days before ovulation.

Accuracy depends on cycle regularity. For regular 28-day cycles: quite accurate (±1-2 days). For irregular cycles: less reliable. Factors affecting ovulation: stress, illness, travel, weight changes. Combine with ovulation tests (LH strips) for better accuracy.

Enter your shortest and longest cycle lengths from the past 6 months. The calculator shows a wider fertile window covering all possible ovulation dates. For very irregular cycles (variation >7 days), consider using ovulation predictor kits alongside.

Yes, for both conception and natural family planning. For conception: focus on the fertile window (5 days before to 1 day after ovulation). For avoidance: abstain or use protection during the fertile window plus a safety margin of 2-3 days on each side.