This tool is for informational use only and is not medical advice. Auburn AI is not a healthcare provider. For anything that affects your health, talk to your doctor or a qualified Canadian health professional.
A calendar-method estimate only – real cycles vary. Not a form of contraception and not medical advice.
About this tool
The Ovulation Calculator estimates your likely ovulation date and fertile window based on the first day of your last menstrual period and your average cycle length. It is designed for people trying to conceive, those tracking their reproductive health, or anyone wanting a clearer picture of their menstrual cycle patterns. Results are estimates based on a standard 28-day model adjusted for your cycle length, not a substitute for medical advice.
Reach for this tool when you are actively trying to conceive and want to time intercourse more accurately, or when you are simply learning how your cycle works. It is also useful for spotting irregularities over several months when you log results consistently. For irregular cycles, treat the output as a rough guide rather than a precise forecast.
How to use it
- Enter the date of the first day of your most recent menstrual period.
- Input your average cycle length in days, typically between 21 and 35.
- Optionally enter your average luteal phase length if you know it.
- Click Calculate to generate your estimated ovulation date and fertile window.
- Review the highlighted fertile days, usually the five days before ovulation plus ovulation day.
- Repeat each month with updated period start dates to track patterns over time.
Pro tips
- Track three or more cycles before drawing conclusions, since a single cycle result can be thrown off by stress or illness.
- Ovulation typically occurs 14 days before your next period, not 14 days after your last one, especially with longer cycles.