Conception Date Calculator by Last Period

FAQs

How does the Conception Date Calculator by Last Period work?

It estimates your conception date based on the first day of your last menstrual period (LMP). By using the average time between ovulation and conception, the calculator provides both an estimated conception day and a possible range of dates when conception could have occurred.

Can this calculator show possible intercourse dates?

Yes. Because conception does not happen immediately after intercourse, the tool estimates a window of days when intercourse most likely led to pregnancy, based on your cycle length and ovulation timing.

How accurate is a conception date calculated from the last period?

The results are an estimate. Conception typically occurs about 11–21 days after the first day of the last menstrual period, but the exact day depends on ovulation. The calculator gives you a likely date range rather than an exact day.

What if my menstrual cycle is irregular?

If your cycles are irregular, the estimation may be less precise. In such cases, an early ultrasound is often more accurate for determining gestational age and conception timing.

Can I save or track my previous calculations?

Yes. With the calculation history feature, you can review past results, compare them, and keep track of different conception date estimates over time.