IVF Calculators

Five free calculators for the dates that matter in an IVF cycle — transfer to test, test to due date. Everything runs in your browser: no accounts, no email, nothing stored.

IVF due date calculator

Day-3, day-5 and day-6 transfers, fresh or frozen.

hCG doubling calculator

Compare two beta results and see the doubling time.

Two-week wait calculator

Test day, beta day and what each day past transfer means.

IVF gestational age calculator

Turn a transfer date into exact weeks and days.

FET cycle calculator

Plan a frozen transfer cycle backwards or forwards.

Which calculator, and when

Planning the cycle

Work out when a frozen transfer would fall, or when a cycle needs to start to hit a particular transfer week.

FET cycle calculator

After the transfer

See your earliest test day, your likely beta date, and what is happening on each day past transfer.

Two-week wait calculator

After a positive beta

Compare two beta results to see the doubling time and the equivalent 48-hour rise.

hCG doubling calculator

Once pregnancy is confirmed

Get your due date from the transfer date, and convert any date into exact gestational weeks and days.

IVF due date calculator

How IVF dating works, in one paragraph

Pregnancy is dated from a notional last period about two weeks before conception, and IVF keeps that convention. On transfer day you are counted as 14 days plus the embryo's age — 2w 5d for a day-5 blastocyst. The due date is the transfer date plus 266 days minus the embryo age. Everything else, from beta timing to the anatomy scan window, follows from those two facts.

Fresh, frozen and ICSI

None of these change the arithmetic. What matters is how old the embryo was at the moment it was placed in the uterus. An embryo frozen on day 5 and thawed two years later is still dated as a day-5 transfer.

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Frequently asked questions