Find your estimated ovulation date and fertile window, with a day by day breakdown of relative fertility.
Estimates only, not medical advice.
Ovulation typically occurs about 14 days before your next period, so this calculator first estimates your next period from your cycle length, then counts back 14 days to place ovulation. The fertile window spans the five days before ovulation through the day after it, six days in total.
Not every day inside the fertile window carries the same odds. The table below shows how this calculator treats the days around estimated ovulation.
| Day relative to ovulation | What this calculator shows |
|---|---|
| 5 days before | Start of fertile window |
| 2 days before | Inside fertile window |
| 1 day before to ovulation day | Most fertile days |
| 1 day after | End of fertile window |
Cycle based estimates like this one work best for people with fairly regular cycles who want a general planning window. If your cycles vary widely month to month, or you have been trying for several cycles without success, ovulation predictor kits, basal body temperature charting, or a conversation with your doctor about fertility testing will narrow things down more precisely than date math alone.
The shareable link above is meant for exactly this kind of tracking: run the calculator once with this month's last period date and cycle length, copy the link, and keep it alongside any temperature or predictor kit readings you are logging elsewhere. Because the link encodes your inputs rather than a stored account, nothing about your cycle is saved on our end. If next month's numbers look different, run the calculator again with the new dates rather than assuming last month's window still applies.
Estimate only, not medical advice. Generated by pregnancy-tools.com
Sperm can survive in the reproductive tract for several days, so intercourse in the days leading up to ovulation can still result in conception even though the egg has not yet been released.
The one to two days immediately before ovulation are generally associated with the highest chance of conception in a given cycle.
Less so. This estimate assumes a fairly consistent cycle length. If yours varies a lot month to month, ovulation predictor kits or cycle tracking over several months will narrow things down better than date math alone.
No. Timing improves the odds within a fertile cycle, but many other factors affect whether conception happens in any given month.