Free Due Date Calculator
Calculate your estimated due date for pregnancy based on your last menstrual period
Select your average cycle length if different from 28 days
- 1Enter the first day of your last menstrual period
- 2Select your average cycle length (if not 28 days)
- 3Click Calculate to determine your estimated due date
- 4View your estimated conception date
- 5Note that this is an estimate - actual delivery may vary
- Start taking prenatal vitamins with folic acid before conception
- Attend regular prenatal checkups to monitor your health and baby's development
- Maintain a healthy diet and stay hydrated throughout pregnancy
Frequently Asked Questions
Understanding Your Pregnancy Due Date
Your pregnancy due date, also known as the estimated date of delivery (EDD), is an important milestone that helps track your pregnancy progress. While calculated as 40 weeks from the first day of your last menstrual period (LMP), it's important to remember that this is just an estimate. In reality, only about 5% of babies are born exactly on their due date, with most arriving between 37 and 42 weeks.
How Due Dates Are Calculated
The standard method for calculating due dates is Naegele's rule, which adds 280 days (40 weeks) to the first day of your last menstrual period. This assumes a regular 28-day cycle with ovulation occurring on day 14. However, if your cycle length differs from 28 days, the due date should be adjusted accordingly. For example, if your cycle is 32 days long, ovulation likely occurs later, so the due date would be pushed back by 4 days.
Factors That Can Affect Your Due Date
- Cycle Length: Longer or shorter cycles affect when ovulation occurs
- Ultrasound Measurements: Early ultrasounds can provide more accurate dating
- Previous Pregnancies: First-time mothers often go longer than those who have given birth before
- Maternal Health: Certain health conditions can influence timing
- Baby's Development: Some babies naturally take longer to develop
Using Our Free Due Date Calculator
Our online due date calculator provides an estimated due date based on the standard 280-day pregnancy calculation. Simply enter the first day of your last menstrual period and your average cycle length (if different from 28 days). The calculator will also estimate your conception date, which is typically about two weeks after the start of your LMP. Remember that this is just an estimate - your healthcare provider may adjust the due date based on ultrasound measurements or other factors.