Pregnancy Due Date Calculator

A due date — clinically an estimated due date, or EDD — is the reference point around which the whole of pregnancy care is organised. It determines when scans and screening tests are offered, how gestational age is tracked, and what counts as early or late. This calculator gives you that date from whichever information you actually have, using four established methods rather than forcing everyone through a single formula. The most familiar method is Naegele's rule, which adds 280 days (40 weeks) to the first day of your last menstrual period. Because that rule assumes a textbook 28-day cycle, this tool also lets you enter your own average cycle length and adjusts the estimate accordingly. If you have had a dating ultrasound, you can enter the scan date and the gestational age your clinician reported — generally the most reliable approach. If you know your conception or IUI date, or you conceived through IVF, dedicated tabs apply the correct offsets, including the precise Day-3 and Day-5 embryo transfer calculations.

Rather than presenting a date and asking you to trust it, this tool shows its work. Expand the "How was this calculated?" panel and you will see the exact arithmetic, step by step, for the method you chose — which is also why different websites sometimes disagree by a day or two. If you enter both an LMP and an ultrasound, you can view the two estimates side by side and see the difference between them. The tool will never silently overwrite one with the other: which date to use is a clinical decision for your provider. Alongside the due date you get your current gestational age in weeks and days, the trimester boundaries, the full-term window, and the typical timing of common milestones such as the anatomy scan and gestational diabetes screening. These windows are informational only — real protocols vary by country, by clinic, and by individual circumstances. Everything runs privately in your browser, and you can export the dates to your calendar or share the link. Please remember that this tool is for education and planning, not a substitute for professional medical care.