A connected set of tools for the whole journey โ from tracking your fertile window to counting the weeks. Each one handles irregular cycles, multiple dating methods, and gives you real dates, not just a number.
Trying to conceive? Find your fertile window and the best days, even with irregular cycles.
Find your ovulation date and fertile window even with irregular cycles. See your next 6 fertile windows, the earliest reliable test date, and export the days to your calendar (.ics).
Got a positive test? Estimate your due date from your last period, conception, IVF transfer, or an ultrasound.
Estimate your due date from your last period (with cycle-length adjustment), conception, an IVF transfer (day 3 or 5), or an ultrasound. Shows the full-term 37โ42 week window and current gestational age.
Already pregnant? See exactly how many weeks and days along you are, plus your prenatal appointment schedule.
See exactly how many weeks and days pregnant you are โ from your last period or an ultrasound โ plus fetal age, trimester, due date, and your prenatal appointment schedule with real dates.
Due dates and gestational age are conventionally counted from the first day of the last menstrual period (LMP), assuming ovulation around day 14 โ so the same 40-week timeline links ovulation, conception, and your current week. Where you know a more precise date (an early ultrasound, a known conception or IVF transfer), these tools use it and reconcile the difference, because early-ultrasound dating is more accurate than LMP for irregular cycles.
These calculators give estimates for planning and education only. They are not medical advice and don't replace your doctor or midwife. Only about 1 in 20 babies arrive on the exact due date.