Pregnancy chances by age

It's called fecundability: the probability that one menstrual cycle of regular, well-timed sex ends in a pregnancy. For a healthy couple in their 20s that's roughly 1 in 4 to 1 in 5 per cycle — which surprises many people, because it means even peak human fertility involves plenty of cycles that don't work out. Nothing went wrong in those cycles; that's just the base rate. It's why clinicians think in months and years of trying, not single cycles, and why a few unsuccessful months tell you very little on their own.

No — and this matters more than any figure on the page. These are averages across large groups of couples, and the spread within any age group is enormous. Your personal chances depend on things no age table can see: whether you ovulate regularly, whether your fallopian tubes are open, sperm count and quality, conditions like endometriosis or PCOS, how well intercourse is timed to the fertile window, and more. A 38-year-old can conceive the first month; a 26-year-old can need help. Use the averages to set expectations and plan — not as a prediction about you.

With a deliberately simple formula: 1 − (1 − p)^n, where p is the average per-cycle chance for the age band and n is the number of cycles. It assumes every cycle carries the same independent chance, which isn't quite how reality works — couples with higher fertility tend to conceive in the early months, some couples in every band can't conceive naturally at all, so the true group-wide curve flattens over time and real 12-month rates run below what the formula suggests. That gap is modest at younger ages but substantial at 40–44: there the formula would imply about 52% within 12 cycles, whereas studies put real-world 12-month pregnancy rates around 30–40% (and live-birth rates lower still). Because that overstatement is large enough to be misleading in exactly the band where over-optimism is most harmful, we don't show projected 6- or 12-cycle numbers for 40+ at all — we quote the observed study range and ACOG's advice to evaluate right away instead. For the younger bands where the simplification is reasonable, we use it because it's transparent and directionally right, and we label it as a simplification everywhere it appears.

ACOG's thresholds: if you're under 35, after 12 months of regular, unprotected sex without conceiving; if you're 35 to 39, after 6 months; and at 40 or older, it's reasonable to start the evaluation right away rather than waiting. See someone sooner at any age if there's a known reason — irregular or absent periods, endometriosis, PCOS, a history of pelvic infection or pelvic surgery, prior chemotherapy or radiation, or a known sperm problem. These are thresholds for starting a conversation, not verdicts, and the evaluation itself covers both partners.

Yes, though the effect is more gradual than for eggs. Sperm quality, motility, and DNA integrity decline slowly with age, time-to-pregnancy gets modestly longer when the male partner is over about 40, and some genetic risks tick up with advanced paternal age. More importantly for practical purposes: a male factor contributes in roughly 40% of couples who have difficulty conceiving, at every age. That's why a semen analysis is a standard, early, inexpensive part of any fertility workup — never something to leave until after the female evaluation is exhausted.

Yes. This tool runs entirely in your browser: your age and how long you've been trying are used on your own device and are never sent to a server, stored, or shared — close the tab and they're gone. We treat reproductive data as sensitive by default, so nothing here creates a record anywhere. It's general educational information based on ASRM and ACOG guidance; it isn't medical advice, a diagnosis, or a fertility test, and it can't tell you your personal chances — only an evaluation can look at those.