Calculate your estimated due date using LMP, conception date, or IVF embryo transfer date. View key pregnancy milestones.
Conception date adds 266 days (38 weeks) to calculate the due date. The LMP equivalent is 14 days before the conception date.
IVF due date = Transfer Date + (280 â 14 â embryo day at transfer) days. Gestational age at transfer is 2 weeks + embryo day.
Your Due Date
About the Due Date Calculator
The Oneyfy Due Date Calculator supports three methods for estimating your baby's expected arrival date. Whether you know your LMP, conception date, or had an IVF transfer, this tool gives you an estimated due date and full pregnancy timeline.
How to Use
Select your calculation method: By LMP, By Conception, or By IVF.
Enter the relevant date.
For LMP, optionally enter your cycle length for more accuracy.
For IVF, select the embryo age at transfer (Day 3, 5, or 6).
Click Calculate Due Date.
How It Works
Naegele's Rule (LMP method): Due Date = LMP + 280 days + (cycle length â 28)
Conception method: Due Date = Conception Date + 266 days (LMP equivalent = Conception â 14 days)
IVF method: Due Date = Transfer Date + (280 â 14 â embryo day). For Day 5: Transfer + 261 days.
Example
IVF Day 5 transfer on April 10, 2024: Due Date = April 10 + 261 days = December 27, 2024. Gestational age at transfer: 2 weeks + 5 days = 2w5d.
Frequently Asked Questions
First-trimester ultrasound dating (based on crown-rump length) is the most accurate method and is often preferred over LMP dating. However, the LMP method is reliable when the LMP date is known and cycles are regular. IVF dating is very accurate because conception timing is precisely known.
Full term is defined as 39â40 weeks. Early term is 37â38 weeks, late term is 41 weeks, and post-term is 42+ weeks. The "early term" and "full term" designations were updated in 2013 by ACOG (American College of Obstetricians and Gynecologists).
In natural conception, ovulation (and thus conception) occurs ~14 days after LMP, and gestational age is counted from LMP. In IVF, the embryo age is known precisely. The gestational age at transfer is: 14 days (equivalent LMP offset) + embryo day. This is added to calculate the equivalent LMP date for standard pregnancy tracking.
Gestational age is the age of the pregnancy in weeks, counted from the first day of the last menstrual period â not from conception. A pregnancy is considered full term at 40 weeks gestational age, even though the embryo itself is only about 38 weeks old.