How does the Pregnancy Countdown Calculator work?
The calculator takes your due date and today's date and computes the exact number of days, weeks, and months remaining. It also works backwards 280 days (40 weeks) from your due date to determine how far along you are and which trimester you're currently in. See also our calculate Diaper Recommended Diaper Size.
How is my estimated due date calculated?
A standard pregnancy lasts about 280 days (40 weeks) from the first day of your last menstrual period. Your doctor may also use an ultrasound measurement or conception date to confirm or adjust the estimate. This calculator works with whatever due date you've already been given.
How accurate is my pregnancy due date?
Estimated due dates are accurate to within about two weeks for most pregnancies. Only around 5% of babies are born on their exact due date. Ultrasound dating in the first trimester tends to be the most precise method.
Can my due date change?
Yes, your due date can be revised by your healthcare provider, especially after an early ultrasound. If your doctor updates your due date, simply re-enter the new date into this calculator to get a fresh countdown.
What if I already know my due date?
This calculator is built exactly for that situation — just enter your known due date and it instantly shows you how many days, weeks, and months remain, your current trimester, and your overall pregnancy progress.
When does each trimester begin and end?
The first trimester covers weeks 1–13, the second trimester runs from weeks 14–26, and the third trimester spans weeks 27–40. The calculator displays your current trimester and the expected start and end dates for each stage based on your due date.
What does 'weeks pregnant' mean on the countdown?
'Weeks pregnant' refers to how many weeks have passed since the first day of your last menstrual period (or the equivalent start of your pregnancy). A full-term pregnancy is 40 weeks, so if you are 30 weeks pregnant, you have approximately 10 weeks remaining.
Is it normal to go past my due date?
Yes, it is quite common. Pregnancies that reach 41–42 weeks are still within the normal range. Your doctor will monitor you closely and discuss options if you go more than a week or two past your due date. You might also find our Cost of Having a Baby Calculator useful.