Pregnancy calculator
This free pregnancy calculator works out your estimated due date and current gestational age from the first day of your last menstrual period (LMP). Pick the date and the tool shows the due date and how far along you are in weeks and days.
How it's calculated
The estimate uses Naegele's rule: the due date is 280 days (40 weeks) from the first day of the last menstrual period. The current gestational age is the number of days since the LMP, shown in weeks and days. This is an average estimate; the real timing can vary.
Example
If the last period started on 1 January, the estimated due date is around 8 October (280 days later). The current week as of today is also shown.
Frequently asked questions
Is the result accurate?
It's an average estimate. The exact date is set by an ultrasound and a doctor's exam.
Which date do I enter?
The first day of your last menstrual period.
Is this medical advice?
No — it's for information only. Consult your doctor.
Is the tool free?
Yes — completely free.