What is the Days Until Baby Is Born Calculator?
This countdown tool tells you exactly how many days are left until your baby's estimated due date. Pregnancy is often measured in weeks, but as the big day approaches many parents prefer a simple day-by-day countdown. Just enter the due date your midwife or doctor gave you, along with today's date, and the calculator shows the days, weeks, and approximate months remaining.
How to use it
Enter your Estimated Due Date — this is the EDD (estimated date of delivery) provided after your dating scan or calculated from your last menstrual period. Then confirm Today's Date (it defaults to today). Press calculate and you'll instantly see how many days remain, the same span shown in whole weeks plus extra days, and a rough month estimate.
The formula explained
The calculator converts both dates to a millisecond timestamp, subtracts today from the due date, then divides by 86,400,000 (the number of milliseconds in one day). The result is rounded up with a ceiling function so a partial final day still counts as a full day to go. Weeks are simply days ÷ 7, and the approximate months figure uses the average month length of 30.4375 days.
$$\text{Days} = \left\lceil \frac{\text{Due Date} - \text{Today}}{86400000\,\text{ms}} \right\rceil$$
Worked example
Suppose today is 1 January 2025 and your due date is 31 January 2025. That span is 30 days, so the calculator shows 30 days remaining, equal to 4 weeks and 2 days, or about 0.99 months. As each day passes the countdown ticks down by one.
FAQ
Is the due date exact? No. Only about 5% of babies arrive on their due date; most arrive within two weeks either side, so treat the countdown as an estimate.
What if the due date has already passed? The calculator will show a negative number, meaning that many days are now overdue.
Why is the months figure approximate? Calendar months vary from 28 to 31 days, so we use the average month length to give a smooth estimate.
