Why IVF Dates Are More Accurate
Standard pregnancy calculators estimate ovulation as Day 14 of a cycle. However, in an IVF cycle, the exact moment of fertilization (Egg Retrieval Day) or the exact age of the embryo (Day 3 or Day 5) is known with certainty.
This makes your IVF due date a precise clinical date rather than an estimate. Doctors rarely change an IVF due date based on ultrasound measurements unless there is a significant discrepancy.
Fresh vs. Frozen Transfers (FET)
Many patients ask if frozen embryos have a different calculation. The answer is no.
Biologically, a Day 5 Blastocyst is 5 days old at the moment of transfer, regardless of whether it was created 5 days ago (Fresh) or 5 years ago (Frozen). The calculator treats them exactly the same.
The "Two Week Wait" (TWW)
The time between your transfer and your blood pregnancy test (Beta hCG) is notoriously difficult emotionally.
- Day 0: Transfer Day.
- Day 1-5: Embryo continues to divide and begins implanting into the uterine lining.
- Day 6-8: HCG hormone begins entering the bloodstream. Home tests might show a faint line, but false negatives are common.
- Day 9-11: Beta Blood Test. Levels generally need to be >5 (or clinic specific cutoff) to confirm pregnancy.
Frequently Asked Questions
How do I calculate gestational age for IVF?
Is my due date guaranteed?
What if I did IUI?
Tools & Data Verified by the EverydayCalculators Medical Research Team.
Last updated: January 2026.