Pregnancy due date calculator
Add 280 days to the first day of the last menstrual period, or 266 days to a conception date. See weeks pregnant and days left. The dates stay in your browser.
This is an estimate from a standard date rule. Actual delivery dates vary, often by days or weeks. It is not a diagnosis. This page does not give personal medical advice. Ask a healthcare provider about anything specific to you.
How the date is counted
The last-period rule adds 280 days to the first day you enter. A cycle other than 28 days moves that date by the difference: a 30 day cycle adds 2 days, and a 26 day cycle subtracts 2 days. For 1 January 2026 and a 28 day cycle, the due date is 8 October 2026.
Conception mode adds 266 days and does not use the cycle length. 266 is 280 minus 14, the usual two-week offset. A conception date of 15 January 2026 lands on the same 8 October 2026 due date.
Weeks pregnant are counted from the last period, or from 14 days before a conception date. The cycle length changes the due date only. Today is the calendar date in Asia/Karachi. If the estimate is already past, the page says how many days ago it fell.
Questions
What is Naegele's rule?
Naegele's rule estimates a due date by adding 280 days to the first day of the last menstrual period. That span is 40 weeks. This page uses that rule, and a cycle other than 28 days shifts the date by the same number of days. The result is an estimate, not a diagnosis.
How does the conception date mode work?
Conception mode adds 266 days to the date you enter. That is 14 days shorter than the 280 day last-period rule, because ovulation often falls about two weeks after a period on a 28 day cycle. A conception date of 15 January 2026 matches a last period of 1 January 2026.
What does cycle length change?
On last-period mode, the cycle length changes only the due date. A 30 day cycle adds 2 days, and a 26 day cycle subtracts 2 days. Weeks pregnant are still counted from the last period. Conception mode ignores the cycle field. Leave the field blank and the page uses 28 days.
Is this a medical diagnosis?
No. Real births often arrive days or weeks earlier or later than this estimate. The page does not know ultrasound dates, medical history, or how a pregnancy is progressing. It does not diagnose anything, and it does not give personal medical advice. Ask a healthcare provider about your own dates.