Find your most fertile days and best time to get pregnant using your cycle data.
Enter your cycle info on the left, then tap Calculate.
👉 Success Tip: Tracking your LH surge with an ovulation kit is the most accurate way to confirm the fertile window our calculator has estimated for you.
The #1 choice for tracking LH surges and confirming timing throughout your entire cycle.
View on AmazonThe best time to get pregnant is during the 2 days leading up to ovulation and the day of ovulation itself. This ensures sperm are present when the egg is released.
If your cycles are irregular, calendar methods are less reliable. We recommend combining this calculator with ovulation predictor kits (OPKs) for better accuracy.
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Most women are most fertile around 10–14 days after the first day of their last period, assuming a 28-day cycle. For shorter or longer cycles, ovulation shifts accordingly — with a 30-day cycle, ovulation typically occurs around day 16. Use the calculator above with your actual cycle length for a precise date.
The fertile window is the 6-day period when pregnancy is possible — the 5 days before ovulation and the day of ovulation itself. This window exists because sperm can survive up to 5 days inside the female reproductive tract, meaning intercourse before ovulation can still lead to pregnancy.
The best days to get pregnant are the 2 days before ovulation and the day of ovulation — these 3 days give you the highest probability of conception per cycle, around 25–30%. Having intercourse every 1–2 days throughout your entire fertile window further maximizes your chances.
To calculate your fertile window, subtract 14 days from your cycle length to find your ovulation day, then count back 5 days from ovulation — that 6-day range is your fertile window. For example, with a 28-day cycle, ovulation is around day 14, so your fertile window is days 9–14. Our calculator does this automatically.
For a typical 28-day cycle with a 5-day period, you could get pregnant from around day 9 onwards (4 days after your period ends), as this is when the fertile window begins. With shorter cycles (21–24 days), the fertile window can start as early as day 4–6, meaning you may be fertile while still on your period.
It is very unlikely but possible. Cycle lengths can vary month to month, meaning ovulation may occur earlier or later than predicted. This is why using ovulation predictor kits (OPKs) alongside a calculator gives you more accurate confirmation of your actual fertile window each cycle.
The best time to get pregnant calculator above works by taking your last period date and average cycle length, calculating your ovulation date, and showing your full 6-day fertile window. It also highlights your 3 peak days — the 2 days before ovulation and ovulation day itself — when conception chances are highest.