Pregnancy Due Date Calculator
Find out when your baby is due. Enter the first day of your last menstrual period and your average cycle length to see your estimated due date, current week of pregnancy, and trimester.
Typical range: 21-40 days
Due Date
Saturday, October 10, 2026
Current Week
Week 10 of 40
Trimester
1st Trimester
Days Remaining
210 days
70 of 280 days completed
How to use this calculator
- Select the first day of your last menstrual period.
- Enter your average cycle length (default is 28 days).
- View your estimated due date, current week, and trimester.
How it works
Our Pregnancy Due Date Calculator uses Naegele's rule, the standard method used by doctors and midwives worldwide, to estimate your due date.
How Naegele's rule works
The estimated due date (EDD) is calculated by adding 280 days (40 weeks) to the first day of your last menstrual period (LMP). If your cycle is longer or shorter than the standard 28 days, the calculator adjusts accordingly: for each day your cycle differs from 28, the due date shifts by that many days.
What the results show
- Due date: Your estimated delivery date. - Current week: How far along you are in your pregnancy (weeks since LMP). - Trimester: First (weeks 1-12), second (weeks 13-27), or third (weeks 28-40). - Days remaining: How many days until your due date.
How accurate is this?
Only about 5% of babies are born on their exact due date. Most births occur within two weeks before or after the EDD. An ultrasound in the first trimester provides a more accurate estimate. This calculator gives a reliable starting point based on menstrual dates.
When to see your doctor
Use this calculator for an initial estimate, then confirm with your healthcare provider. If your cycle is very irregular or you are unsure of your LMP date, an early ultrasound (6-9 weeks) can provide a more precise dating.
Using Naegele's rule: add 280 days (40 weeks) to the first day of your last menstrual period, adjusted for cycle length.
About 5% of babies arrive on their exact due date. Most are born within 2 weeks of the EDD. First-trimester ultrasound is more accurate.
If you are unsure, consult your healthcare provider for an ultrasound-based estimate.
Yes. If your cycle is 35 days instead of 28, your due date shifts about 7 days later. The calculator adjusts automatically.
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