Free tools
Due date & ovulation calculators.
Two quick answers, worked out on your own phone — nothing you type here is saved, sent or seen by anyone.
These are estimates based on your last period, not a diagnosis. An ultrasound scan dates a pregnancy far more accurately — book a scan to be sure.
Good to know
How these are worked out
The due date uses the standard method doctors use — roughly 40 weeks from the first day of your last period — adjusted for your own cycle length, because a longer cycle means you ovulate later.
The fertile window is the handful of days around ovulation when conception is most likely. Ovulation happens about two weeks before your next period, not two weeks after the last one, which is why the cycle length matters.
Both are estimates. Cycles vary, and an early ultrasound scan will always date a pregnancy more accurately than any calculator can.