Calcolatrice data di concezione
The detailed guide below is currently available in English.
How conception is estimated backwards
Pregnancy dating traditionally starts from the last menstrual period and assumes ovulation about two weeks later. That makes the interval from conception to the estimated due date almost exactly 266 days. Working backwards from a known due date — or forwards from a last period — gives the most likely day of conception, shown here as the headline result. An ultrasound measurement dates the pregnancy directly, so it is the closest to a precise answer.
Why a window matters
Sperm can survive several days in the reproductive tract, and ovulation rarely lands exactly 14 days after the period for every person or every cycle. The five-day window shown in the results reflects that spread: conceptions from intercourse in the days before the central date are entirely normal. For already-born babies, remember that due dates themselves are estimates, so a birth weeks early or late shifts the implied conception day equally. All outputs are estimates, not medical advice.
Domande frequenti
Can a due date tell me the exact day I conceived?
No. Due dates are population averages, and ovulation varies by several days even in regular cycles. The calculator gives the most statistically likely date plus a window; only early ultrasound dating comes close to a precise answer.
Why does gestational age say 2 weeks at conception?
Clinical gestational age is counted from the last menstrual period, roughly two weeks before conception. So on conception day a pregnancy is already called "2 weeks" even though the embryo itself has just begun to form.
Which method is the most accurate?
An early ultrasound (first trimester) measures the embryo directly and typically dates conception within a few days. Due-date and last-period methods rely on averages of cycle length and ovulation timing.