Ovulation & Period Calculator
Find your fertile days and next period date
First day of your last period · Cycle length · Period lasts
How fertile days are calculated
In most women, ovulation happens about 14 days before the next period. The fertile window is the 5 days before ovulation and ovulation day itself, because sperm can live for up to 5 days and the egg for about a day. So with a 28-day cycle, ovulation is around day 14 and the most fertile days are about days 9 to 14. The first day of your period is day 1.
This is an estimate for regular cycles. Please do not use it as birth control. If your periods are irregular, very painful or very heavy, see a gynaecologist.
Your dates stay on your phone. They are worked out right here and are never sent to ProMedicoz, never saved and never shared with anyone.
Frequently asked questions
When am I most likely to get pregnant?
In the 2–3 days before ovulation and on ovulation day. Having sex every 2–3 days through the fertile window gives the best chance.
How accurate is an ovulation calculator?
It is a good estimate if your cycles are regular. Ovulation can shift with stress, illness or travel. Ovulation test kits or a scan by your doctor are more exact.
Can I use this to avoid pregnancy?
No. Calendar estimates are not reliable as birth control. Please talk to a doctor about contraception.
What if my periods are irregular?
If your cycle often changes by more than 7–9 days, this calculator will be less accurate. Irregular periods can have causes like PCOS or thyroid problems, so it is worth seeing a gynaecologist.
When should I see a doctor about getting pregnant?
If you have been trying for a year (or 6 months if you are over 35), or sooner if your periods are irregular or very painful.
Read next
- Trying to Conceive: A Practical Guide to Getting Started
- Understanding Your Menstrual Cycle: What Is Normal and What Is Not
- PCOS/PCOD Explained: Irregular Periods, Weight & What Really Helps
- PMS: Understanding Premenstrual Symptoms and Getting Relief
- Painful Periods: Why Cramps Happen and How to Get Real Relief
- Think You Might Be Pregnant? Early Signs and First-Trimester Care
- Pregnancy due date calculator
- Find a gynaecologist