Pregnancy Due Date Calculator
Calculate your estimated pregnancy due date (EDD) quickly and easily. Enter the first day of your last menstrual period and average cycle length to get custom milestone tracking and trimester schedules.
Input Metrics
Trimester Schedules
- 1st Trimester (0-13 Weeks) --
- 2nd Trimester (14-27 Weeks) --
- 3rd Trimester (28+ Weeks) --
Key Milestones
- Heartbeat Audible (Week 8) --
- Anatomy Scan (Week 20) --
- Third Trimester (Week 28) --
How to Use the Pregnancy Due Date Calculator
Getting an estimate of your due date is simple. Follow these steps to map your milestones:
- Select the First Day of your Last Menstrual Period (LMP) using the calendar date picker.
- Adjust the Average Cycle Length slider. The default setting is 28 days, but you can customize it from 21 to 35 days to match your body.
- Click Calculate Due Date to view your Estimated Due Date (EDD), your current progress week, and dates for upcoming key medical milestones.
Naegele's Rule: How the Due Date is Calculated
The calculator estimates your due date using Naegele's rule, which assumes a standard pregnancy is 280 days (40 weeks) from the LMP:
If your average cycle is longer than 28 days, it is assumed that ovulation occurred later, so those extra days are added to the due date. If it is shorter, the due date is adjusted earlier.
Frequently Asked Questions
How is my pregnancy due date calculated? ↓
The pregnancy due date is calculated using Naegele's rule: adding 280 days (40 weeks) to the first day of your last menstrual period (LMP). It is adjusted based on your average cycle length.
What if my cycle is not 28 days long? ↓
If your cycle is longer or shorter than the standard 28 days, the due date is adjusted. For example, a 30-day cycle adds 2 days to your due date, while a 26-day cycle subtracts 2 days.
Can I calculate my due date if I do not know my LMP? ↓
If you do not know the date of your last period, a healthcare professional can determine your due date using an ultrasound scan, which measures the gestational age of the baby.
How accurate is a pregnancy due date? ↓
A due date is an estimate. Only about 4% of babies are born exactly on their due date. Most babies arrive within a two-week window before or after the estimated date.
What are the three trimesters of pregnancy? ↓
Pregnancy is divided into three trimesters: the First Trimester (weeks 1 to 13), the Second Trimester (weeks 14 to 27), and the Third Trimester (weeks 28 to birth).