Work out your estimated due date and how far along you are.
Choose a date and press Calculate.
Most cycles are 28 days.
The first day of your last period, or the date of conception if you know it.
For a last period, also set your average cycle length.
See your due date, the end of each trimester and the weeks pregnant today.
By Naegele's rule: 280 days (40 weeks) from the first day of the last period, adjusted if your cycle is longer or shorter than 28 days. From conception, it is 266 days.
It is an estimate. Only about 5% of babies arrive on the due date, and a birth between 37 and 42 weeks is normal. Your doctor may change the date after an ultrasound.
The first trimester ends at the end of week 13 and the second at the end of week 27.
No. It is calculated in your browser. General guidance for adults, not medical advice.