How the Egg Freezing Calculator Works
This calculator estimates outcomes from egg freezing using the same "embryology cascade" that fertility clinics use to counsel patients: each mature egg you freeze has to survive thawing, fertilize, develop into a blastocyst, and turn out to be chromosomally normal (euploid) before it has a real chance of becoming a live birth. Multiplying published success rates for each of those steps — and adjusting the chromosomal-normalcy step for your age — produces an estimate of how many usable embryos a batch of frozen eggs is likely to yield, and your resulting chance of at least one live birth.
The embryology cascade, step by step
Starting from your mature (MII) egg count, the calculator applies four published rates in sequence: (1) post-warming survival, about 90% for eggs frozen by vitrification; (2) fertilization, about 75% of surviving eggs fertilize with ICSI; (3) blastocyst formation, about 50% of fertilized eggs develop into a day 5-6 blastocyst; and (4) euploidy, the age-dependent share of blastocysts that are chromosomally normal. Multiplying eggs frozen × 0.90 × 0.75 × 0.50 × euploidy rate gives the estimated number of euploid blastocysts available for future transfer. Each euploid blastocyst then carries roughly a 55% chance of resulting in a live birth per transfer, so the chance of at least one live birth from N euploid blastocysts is estimated as 1 − (1 − 0.55)^N.
Why age drives the biggest changes
Egg quantity matters, but egg quality — specifically the chance that an egg's chromosomes are normal — changes the most with age. Comprehensive chromosomal screening of blastocysts (Franasiak et al., 2014) found euploidy rates around 60% under age 35, roughly 45-52% between 35 and 40, and well under 20% after age 42. Because this calculator holds survival, fertilization, and blastocyst rates constant and only varies euploidy by age, it isolates why the "recommended mature eggs" benchmark rises so steeply for women freezing eggs later.
Talk to a reproductive endocrinologist before deciding
This tool applies population-average statistics to your inputs; it is an educational estimate, not a personal diagnosis, prognosis, or medical order. Your own ovarian reserve (AMH, antral follicle count), egg and sperm quality, uterine health, and the specific lab's protocols all shift your real odds up or down. Use this calculator to frame a conversation with a reproductive endocrinologist about how many eggs to freeze and whether more than one retrieval cycle makes sense for your goals.