How to use it
- Enter the first day of your last menstrual period in the format MM/DD/YYYY.
- Click the Calculate button.
- Read the estimated due date and weeks along displayed.
What it does – You enter the first day of your last menstrual period and the calculator adds exactly 280 days (Naegele’s rule) to produce an estimated due date and the current pregnancy week.
Why it matters – Knowing the due date lets you coordinate prenatal visits, arrange maternity leave, budget for baby gear, and set realistic expectations for labor timing. It also helps healthcare providers monitor growth milestones.
How to read the result – The “Estimated due date” line shows the calendar date you’re most likely to give birth. The “Weeks along” line indicates how many weeks have elapsed since the first day of your last period, rounded to the nearest whole week. This is an estimate; about 80 % of babies are born within two weeks before or after the shown date. Use the information to plan appointments, classes, and personal milestones.
Pro tips
- Add a buffer of a few days if your cycle isn’t exactly 28 days.
- Round the weeks up or down based on the day of the week you entered.
- Use the result to schedule your first prenatal visit around 8‑10 weeks.
- Double‑check the date format (MM/DD/YYYY) to avoid calculation errors.
Real-life examples
- A first‑time mom wants to know when to book her maternity leave.
- A couple planning a gender‑revealing party needs the due date to set the timeline.
- A healthcare worker needs a quick estimate for a patient’s prenatal schedule.
Case study
Emily entered 01/06/2024 as the first day of her last period. The calculator returned a due date of 10/12/2024 and 12 weeks along. With this clear timeline, she booked her 10‑week scan, arranged her 12‑week maternity leave, and felt confident planning her baby shower.