Due Date Calculator
Estimate your pregnancy due date and see key milestones. Based on Naegele’s rule — the standard method used by healthcare providers.
How to Use
- Choose whether to calculate from your last menstrual period or conception date.
- Enter the relevant date.
- If using LMP, adjust the cycle length if it differs from 28 days.
- Click “Calculate Due Date” to see your estimated due date and milestones.
Frequently Asked Questions
How accurate is a due date calculator?
Only about 5% of babies are born on their exact due date. Most are born within 1-2 weeks before or after. The due date is an estimate — your healthcare provider may adjust it based on ultrasound measurements.
What is Naegele’s rule?
Naegele’s rule estimates the due date by adding 280 days (40 weeks) to the first day of the last menstrual period. This assumes a 28-day cycle with ovulation on day 14.
What if my cycle is not 28 days?
If your cycle is longer or shorter than 28 days, the calculator adjusts accordingly. Ovulation typically occurs 14 days before the next period, so cycle length affects the due date calculation.
What does “full term” mean?
A pregnancy is considered full term at 39 weeks. Early term is 37-38 weeks. Most healthcare providers consider 37+ weeks safe for delivery.