Estimate the most likely date you conceived from your last menstrual period, your estimated due date, or a known gestational age. Conception usually happens around ovulation, roughly two weeks after the first day of your last period in a typical 28 day cycle, so this tool works backward from the information you have to place a probable conception window rather than a single exact day. It is useful for satisfying curiosity, understanding a pregnancy timeline, or roughly narrowing down which encounter aligns with the dates, while remembering that sperm can survive several days and the fertile window spans a few days around ovulation. Choose whether you know your last period, your due date, or your current weeks pregnant, enter the date, and see the estimated conception date and a likely range. Everything is calculated in your browser, and this is general information, not medical advice. An early ultrasound gives the most accurate dating.
Estimate the most likely date you conceived from your last menstrual period, your estimated due date, or a known gestational age. Conception usually happens around ovulation, roughly two weeks after the first day of your last period in a typical 28 day cycle, so this tool works backward from the information you have to place a probable conception window rather than a single exact day.
Yes. Conception Date Calculator is completely free, with no sign-up and no usage limits.
Yes. Conception Date Calculator runs in any modern web browser. There is nothing to download or install.
Yes. Conception Date Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.