IVF Due Date Calculator
Enter your embryo transfer details to estimate your pregnancy due date and key milestones.
This tool provides an estimate only and does not replace guidance from your fertility clinic or OB team.
What is an IVF transfer due date calculator?
An IVF transfer due date calculator estimates your expected delivery date based on the exact day your embryo was transferred and the embryo’s developmental age. Unlike standard pregnancy calculators that rely on the first day of your last menstrual period (LMP), IVF dating is often more precise because fertilization timing is known.
This is especially helpful after a frozen embryo transfer (FET), day-3 transfer, day-5 blastocyst transfer, or day-6 transfer, where pregnancy dating can feel confusing if you use general online calculators.
How the IVF due date formula works
Core formula
Estimated due date = Transfer date + (266 - embryo age in days)
- Day-3 transfer: transfer date + 263 days
- Day-5 transfer: transfer date + 261 days
- Day-6 transfer: transfer date + 260 days
The 266-day number is based on average gestational timing from fertilization to full-term delivery. Because IVF gives a known embryo age, the due date estimate can be adjusted with more confidence than in spontaneous conception dating.
How to use this calculator
- Choose your embryo transfer date.
- Select embryo age at transfer (day 3, day 5, day 6, or custom).
- Click Calculate Due Date.
- Review your estimated due date, equivalent LMP date, and milestone dates.
If you are not sure whether your transfer was day 5 or day 6, check your transfer paperwork or portal summary from your IVF clinic.
Why IVF due dates can still change
Even with IVF, your provider may slightly update dating after early ultrasound findings. This is normal. A due date is always an estimate, not an exact prediction of delivery day.
- Most babies are not born exactly on their due date.
- Ultrasound measurements may refine estimated gestational age.
- Medical factors can affect timing of labor or recommended delivery.
IVF milestones to track after transfer
Early pregnancy period
- Beta hCG testing: usually around 9–14 days after transfer (clinic-dependent).
- Early viability scan: commonly around 6–7 weeks gestation.
- End of first trimester: approximately 13 weeks 6 days.
Second and third trimester milestones
- Anatomy scan: around 18–22 weeks.
- Third trimester: begins at 28 weeks.
- Full term: starts at 39 weeks.
Frequently asked questions
Is IVF due date calculation different from natural conception?
Yes. IVF dating uses a known embryo age and transfer date, while natural conception calculators estimate timing from LMP and ovulation assumptions.
Does frozen embryo transfer change the due date formula?
No. Fresh and frozen transfers use the same dating logic. What matters is the transfer date and embryo age at transfer.
What if I transferred two embryos?
Due date estimation is still based on transfer date and embryo developmental age. Twin status affects pregnancy care but not the underlying dating formula.
Can this tool replace my doctor’s due date?
No. Use this calculator for planning and understanding timelines, then follow your fertility clinic and obstetric provider for official dating and medical decisions.
Final note
IVF patients often want clear timelines after transfer. A reliable due date estimate can make appointments, milestones, and emotional planning easier. Use this calculator as a practical guide, and always confirm next steps with your clinical team.