When Am I Ovulating?
Estimate your ovulation day and 6-day fertile window in seconds. Enter the first day of your last period and your average cycle length — we'll do the rest.
How the ovulation calculator works
1. Your last period
The first day of your last period is day 1 of your cycle — the anchor point for every prediction.
2. Your cycle length
Most cycles are 21–35 days, with 28 being the average. Ovulation happens roughly 14 days before your next period.
3. Your fertile window
The 5 days before ovulation and the day of ovulation itself are when you're most likely to conceive.
Ovulation calculator FAQs
Is ovulation always 14 days before my next period?
It's a common estimate and works well for most people, but it can vary. The luteal phase (from ovulation to your next period) is usually 12–16 days.
How accurate is an ovulation calculator?
Calculators are a great starting point but they're based on averages. If your cycles are irregular, tracking basal body temperature, cervical mucus or using ovulation test strips will give a more accurate picture.
What is the fertile window?
The fertile window is the 5 days before ovulation plus the day of ovulation itself — 6 days in total. Sperm can survive up to 5 days inside the reproductive tract, so timing intercourse anywhere in this window gives you a chance of conceiving.
Can I use this calculator if my cycles are irregular?
You can, but the results will be less reliable. Consider tracking your cycles for a few months first, or speak with a fertility specialist if your cycles vary by more than 7–9 days.
When should I speak to a fertility specialist?
If you've been trying to conceive for 12 months without success (or 6 months if you're 35+), it's worth getting checked. You can find trusted fertility clinics and experts across the Babble Connect directory.
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