How long does a frozen embryo transfer cycle take?

A medicated FET cycle usually runs about three weeks from the start of your period to transfer day, then another nine days or so to the beta test. Natural cycle FETs follow your own ovulation and vary more.

When in the cycle is a frozen embryo transferred?

In a medicated cycle the transfer is timed by progesterone: a day-5 blastocyst is transferred after about five full days of progesterone. In a natural cycle it is timed from ovulation instead, again about five days later for a blastocyst.

What lining thickness is needed for a transfer?

Most clinics want a triple-layer pattern of roughly 7 mm or more before starting progesterone. If the lining is thinner, the cycle is usually extended rather than cancelled.

What is the difference between a medicated and a natural FET?

A medicated cycle uses estrogen and progesterone to build and time the lining, giving the clinic full control of the transfer date. A natural cycle tracks your own ovulation, involves fewer medications, but offers less flexibility on dates.

Can I choose my transfer date?

Within limits. Medicated cycles can often be shifted by a few days by adjusting the estrogen phase, which is why they are common when clinic or travel scheduling matters. Your clinic decides what is safe in your case.

Does a frozen transfer change the due date?

No. The due date is calculated from the transfer date and the embryo's age, not from when the embryo was created or frozen.

FET Calculator

Map out a frozen embryo transfer cycle. Start from the first day of your period to see when transfer would fall, or start from a target transfer date to see when the cycle needs to begin.

Cycle type

Plan from

First day of your period

Embryo age at transfer

Transfer day

Friday, October 16, 2026

Estimated due date if successful

Sunday, July 4, 2027

This is an estimate for information only — only about 1 in 20 babies arrive on their due date. Always confirm dates with your midwife or doctor.

Your medicated FET timeline

Protocols vary widely between clinics. These are typical timings — your clinic's calendar always takes priority.

Stage	Date	Notes
Cycle day 1 (period starts)	Sun, Sep 27	Baseline scan and bloods are usually around now.
Estrogen (estradiol) starts	Tue, Sep 29	Typically cycle day 2-3, building the uterine lining.
Lining check scan	Fri, Oct 9	Around cycle day 12-14; clinics look for roughly 7-8 mm.
Progesterone starts	Sun, Oct 11	Progesterone start sets the transfer date.
Day-5 embryo transfer	Fri, Oct 16	5 full days of progesterone before a day-5 transfer.
Beta hCG	Sun, Oct 25	About 9 days past a day-5 transfer.

How a medicated FET cycle is timed

In a medicated (or "programmed") cycle your own ovulation is set aside and the lining is built with estrogen from around day 2-3 of your period. After roughly two weeks a scan checks the thickness and pattern. Once the clinic is happy, progesterone starts — and that is the moment that fixes the transfer date, because the lining is only receptive for a short window afterwards. A day-5 blastocyst goes back after five full days of progesterone; a day-3 embryo after three.

How a natural cycle FET differs

A natural cycle relies on your own ovulation. Monitoring starts around day 9-10 with scans and LH testing, and the transfer is timed from the surge or from a trigger injection. Fewer medications, but the dates move with your body rather than the clinic's diary.

Working backwards from a date

If you need a transfer to land in a particular week — around work, travel or childcare — switch the calculator to "Transfer date" and it will show which cycle you need to start. Bring that to your clinic rather than assuming it: estrogen phases can often be stretched, but not indefinitely.

After the transfer

The two-week wait calculator covers the days between transfer and beta, and the IVF due date calculator explains the dating in full.

More IVF calculators

All IVF calculators & guides →