Enter the first day of your last menstrual period
Average menstrual cycle length (20–45 days)
Ready to calculate
Enter your date and click Calculate// estimate your due date from lmp or conception
Calculate your pregnancy due date instantly from last menstrual period or conception date. Get your estimated delivery date, trimester info, and week-by-week timeline.
Ready to calculate
Enter your date and click CalculateSelect LMP (last menstrual period) or conception date — whichever you know.
Type or pick the date from the calendar input field.
Click Calculate to see your estimated due date, trimester, weeks pregnant, and milestone timeline.
This tool calculates your estimated due date (EDD) using the standard Naegele's rule — adding 280 days (40 weeks) to the first day of your last menstrual period. You can also enter a conception date directly for a more personalised estimate. Cycle length adjustment is included for irregular cycles.
The most common method is Naegele's rule: add 280 days (40 weeks) to the first day of your last menstrual period (LMP). For custom cycle lengths, the calculator adjusts accordingly — shorter cycles shift the date earlier, longer cycles shift it later.
Switch to the "Conception Date" method and enter the date you believe conception occurred. The calculator adds 266 days (38 weeks) from conception, which is equivalent to 40 weeks from LMP.
This calculator gives an estimated due date based on standard obstetric formulas. Only about 5% of babies are actually born on their due date. Your OB/GYN may adjust your EDD based on ultrasound measurements.
The first trimester runs from week 1 to week 13. The second trimester runs from week 14 to week 27. The third trimester runs from week 28 to week 40 (delivery). Each trimester brings distinct developmental milestones for your baby.
Pregnancy is measured from the first day of your last menstrual period, not from conception. So at the time of conception (roughly 2 weeks after LMP), you are considered "2 weeks pregnant" in obstetric terms.
No — this tool is for informational purposes only and should not replace medical advice. Always confirm your due date and pregnancy progression with your healthcare provider, who may use ultrasound for more precise dating.
Finding out you're pregnant is one of life's most exciting moments — and one of the first questions on every new parent's mind is: when is my baby due? Our free Pregnancy Due Date Calculator helps you estimate your expected delivery date (EDD) in seconds, using either the date of your last menstrual period (LMP) or your estimated conception date.
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This calculator uses two widely accepted obstetric methods to estimate your due date:
Your estimated due date is calculated at exactly 40 weeks of gestation, counted from the first day of your last menstrual period. In reality, a full-term pregnancy can last anywhere from 37 to 42 weeks. Only approximately 5% of babies are born on their exact due date. Most births occur within a two-week window on either side of the EDD.
Your OB/GYN may also refine your due date based on measurements from your first-trimester ultrasound, which is considered more accurate than LMP dating — especially if your cycles are irregular.
Pregnancy is divided into three trimesters, each lasting approximately 13 weeks:
Our calculator highlights several important dates throughout your pregnancy:
If your menstrual cycle is shorter or longer than the average 28 days, the standard Naegele's rule may not give you the most accurate estimate. Our calculator includes a cycle length adjustment field — simply enter your average cycle length (between 20 and 45 days), and the calculator will shift the EDD accordingly. For example, a 35-day cycle pushes the EDD 7 days later than the standard calculation would suggest.
For the most accurate dating, your healthcare provider may order a dating ultrasound, typically performed between 8 and 12 weeks of pregnancy.
This Pregnancy Due Date Calculator is provided for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of your doctor, midwife, or other qualified healthcare provider with any questions you may have regarding your pregnancy.