Pregnancy Due Date Calculator
Estimate your baby’s due date from your last menstrual period
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Important Information
Pregnancy Due Date Calculator: How to Use It
This calculator estimates an expected due date from the information you enter. A due date is an estimate, not a promise of the exact day a baby will be born. Pregnancy dating can depend on the first day of the last menstrual period, cycle length, ovulation timing and ultrasound findings. Use this tool for general information and confirm pregnancy dating with your qualified maternity-care professional.
How to use the calculator
- Choose the dating method requested. The tool may ask for the first day of your last menstrual period or another date. Use the method you can answer accurately.
- Enter the date carefully. Check day, month and year. Date-format mistakes can shift the estimate by weeks.
- Consider your usual cycle length if requested. A standard calculation often assumes a 28-day cycle. If your cycles are irregular or longer or shorter than that, the result may be less accurate.
- Read the estimated date and pregnancy-week information together. These values are calculated from the input and are not confirmation of fetal growth or pregnancy health.
- Share the estimate with your maternity-care professional. They can compare it with your history and any recommended ultrasound dating and update the estimate when appropriate.
Example of an estimate
If someone enters the first day of their last menstrual period, a common calendar method estimates a due date about 40 weeks from that date. This method assumes a typical cycle and does not directly identify the day of conception. If ovulation happened earlier or later than expected, or the cycle is irregular, the estimate may differ. This is an explanation of the method, not an individual pregnancy calculation or a substitute for clinical assessment.
Why can the estimated date change?
Menstrual dates may be uncertain, cycles vary, and ovulation does not occur on the same day for everyone. An early ultrasound may provide additional information for dating, depending on clinical circumstances and local guidance. Your clinician will interpret the information in context rather than relying only on an online calculator. A due date also does not predict exactly when labour will begin.
What to do after calculating
- Arrange or continue antenatal care and ask your care team how pregnancy dating should be confirmed.
- Keep a note of the date you entered and the estimate shown so you can discuss any difference with your clinician.
- Use the calculator for planning only. Do not use it to decide whether symptoms are safe to ignore or to change medicines or treatment.
- Contact a qualified maternity-care professional if you are unsure whether you may be pregnant, have irregular periods or have conflicting dates.
Frequently asked questions
Is the due date exact?
No. It is an estimate. Many babies are born before or after the estimated date.
Does the calculator tell me the conception date?
No. A due date calculation cannot reliably identify an exact conception date. Ovulation and conception timing can vary.
What if I do not remember my last period?
Do not guess and rely on the result as confirmed. Tell your maternity-care professional that the date is uncertain so they can advise on appropriate dating.
Can I use this calculator to check whether my pregnancy is healthy?
No. A due date calculator cannot assess fetal development, pregnancy viability or medical complications. Those require appropriate clinical care.
When should I seek urgent help?
If you have severe pain, heavy bleeding, fainting or another symptom that feels urgent, seek prompt medical care rather than relying on an online date estimate.
Health disclaimer
This calculator is for educational use and does not provide medical diagnosis or prenatal care. Pregnancy dates and care decisions should be confirmed with a qualified healthcare professional. Follow local maternity-care guidance and seek urgent assessment for concerning symptoms.
An AI Pregnancy Due Date Calculator is an advanced health-tech tool designed to predict your estimated date of delivery (EDD). While traditional calculators simply add 280 days to your last period, an AI-driven tool cross-references multiple personal data points—such as your menstrual cycle history, ovulation patterns, ultrasound biometric markers, or IVF transfer dates—to give you a far more accurate delivery window.
What Makes an AI Calculator Different?
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Personalized Cycle Intelligence: Traditional tools assume every woman has a standard 28-day cycle with ovulation on Day 14. An AI calculator adapts to irregular, shorter, or longer cycles.
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Discrepancy Reconciliation: If your ultrasound scan date differs from your period-based calculation, the AI analyzes clinical criteria (like Crown-Rump Length) to determine which metric is more reliable.
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Probabilistic Arrival Windows: Instead of giving you just one rigid date (since only about 5% of babies arrive on their exact due date), AI predicts a dynamic window showing the highest probability dates for going into labor.
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Full Timeline Generation: Automatically maps out key pregnancy checkpoints, including optimal windows for trimester transitions, genetic screenings, and anatomy scans.