Three quick calculators
The three patients ask for most. They work entirely in your browser — nothing you type is sent anywhere or stored.
These are estimates, not a diagnosis. Only about one baby in twenty arrives on the estimated date, and a dating scan is more accurate than any calculation from a remembered date. Bring the result to your appointment rather than relying on it.
Due date calculator
Pregnancy is dated from the first day of your last period, not from conception — which is why you are considered four weeks pregnant about two weeks after conceiving.
If your cycle is not 28 days, enter its length: ovulation shifts with cycle length, but the second half of the cycle stays about the same.
Ovulation calculator
Estimates the day you ovulate and the fertile window around it. The window opens before ovulation rather than after, because sperm survive several days and the egg only about one.
Cycles vary, and stress, illness and travel all move ovulation. Treat this as a guide to timing, not a guarantee.
IVF due date calculator
After IVF or ICSI the dates are known exactly rather than estimated, so this is the most accurate of the three. Choose the day the embryo was transferred and how old it was.
A day-5 blastocyst is two days further along than a day-3 embryo, so the same transfer date gives a due date two days earlier.
Questions about your dates?
A scan settles it properly. Message the clinic to arrange one.