How the fertile window works
Ovulation — when an ovary releases an egg — typically happens about 14 days before your next period starts. Because sperm can live in the body for up to five days, your fertile window opens about five days before ovulation and closes the day after. This calculator estimates that window from your last period and cycle length, and projects your next three cycles.
Trying to conceive in Canada
Preconception care is covered by provincial health insurance. A family doctor can check your health before pregnancy, review medications, and start fertility testing if needed. Don't have a doctor? A walk-in clinic near you can help you get started.
Frequently asked questions
When am I most fertile?
Your fertile window is roughly the five days before ovulation plus ovulation day itself — sperm can survive up to five days, while the egg lives about 24 hours. The two days before ovulation are usually the most fertile.
How accurate is an ovulation calculator?
It's an estimate based on the average that ovulation happens ~14 days before your next period. Real ovulation shifts with cycle length and stress. Ovulation predictor kits (which detect the LH surge) and tracking basal body temperature give more precise timing.
When should I see a doctor about fertility?
If you're under 35 and haven't conceived after 12 months of trying — or under 6 months if you're 35 or older — talk to a family doctor. They can start basic testing and refer you to a fertility specialist if needed.