PATIENT TOOL
Due Date Calculator
Estimate your due date and see which scan or screening happens when — by last period, conception, IVF transfer, or early ultrasound.
In brief — the direct answer
Your estimated due date is 40 weeks (280 days) from the first day of your last menstrual period. IVF pregnancies count from embryo transfer minus embryo age, and a first-trimester ultrasound (CRL) is the most accurate dating method. Enter one date below to see your due date, how far along you are, and the timing of every recommended scan.
Enter what you know
28 is average. Adjust if your cycle is regularly shorter or longer.
Choose a method and enter the date — your due date, current week, and full scan schedule will appear here.
Good to know
- Only about 4–5% of babies arrive exactly on their due date — most arrive within two weeks either side.
- A first-trimester ultrasound (CRL) is the most accurate way to date a pregnancy; your provider may adjust your due date after your dating scan.
- IVF due dates are exact because the embryo age is known — they do not need adjustment by scan.
- If your cycles are irregular or much longer than 28 days, LMP dating can be off by a week or more — an early scan settles it.
Clinical basis
- American College of Obstetricians and Gynecologists (ACOG). Committee Opinion No. 700: Methods for Estimating the Due Date. Obstet Gynecol. 2017.
- Robinson HP, Fleming JEE. A critical evaluation of sonar "crown-rump length" measurements. BJOG. 1975.
- Salomon LJ, et al. ISUOG Practice Guidelines: ultrasound assessment of fetal biometry and growth. Ultrasound Obstet Gynecol. 2019.
Want a specialist to review this with you?
This tool provides general guidance only and does not replace clinical assessment. Our maternal-fetal medicine team reviews cases urgently in Abu Dhabi and Al Ain.