Due Date Calculator

Calculate your estimated due date from LMP or conception date

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About This Tool

Your estimated due date (EDD) is calculated by adding 280 days (40 weeks) to the first day of your last menstrual period (LMP). This is based on Naegele's Rule, the most widely used method by healthcare providers.

Keep in mind that only about 5% of babies are born on their exact due date — most arrive within two weeks before or after.

Medical Disclaimer: This tool is for educational and informational purposes only. It does not provide medical advice, diagnosis, or treatment. Results are estimates only. Always consult a qualified healthcare professional for medical decisions. In an emergency, call 995 (Singapore) immediately.

Your Pregnancy Trimester by Trimester

Each trimester brings major changes for you and your baby. Here is what to expect at each stage.

First Trimester (Weeks 1–13)

Your baby grows from a single cell to a 7cm foetus. Major organs form. Many women experience morning sickness, fatigue, and breast tenderness. Key tasks: confirm pregnancy with OB, schedule first antenatal appointment, take folic acid, avoid alcohol, limit caffeine.

Second Trimester (Weeks 14–27)

The "golden trimester" - Energy returns, morning sickness eases. You will feel baby's first movements (quickening) around weeks 18–22. Key tasks: anomaly scan at 18–22 weeks, glucose screening at 24–28 weeks, track weight gain, plan your hospital choice.

Third Trimester (Weeks 28–40)

Baby gains weight rapidly and prepares for birth. Braxton Hicks contractions are common. Key tasks: hospital bag packed by week 36, birth plan written, learn to time contractions, install car seat, Group B Strep test at 35–37 weeks.

Key Pregnancy Milestones

Week	Baby Development	Action for You
Week 8	Heart beating, all major organs forming	First OB visit, blood tests, dating scan
Week 12	3.6cm long, fingers forming	First trimester screening (OSCAR test)
Week 20	Halfway! Baby can hear you	Detailed anomaly scan (TIFFA scan)
Week 24	Viability threshold - Can survive with support	Glucose tolerance test (GDM screening)
Week 28	Eyes open, can dream	Third trimester begins, increased check-ups
Week 36	Lungs almost ready, baby drops	Pack hospital bag, GBS swab
Week 40	Full term!	Due date - But only 5% of babies arrive on the dot

Browse every week with the Week-by-Week Pregnancy Guide →

How Your Due Date is Calculated

The standard method is Naegele's Rule: add 280 days (40 weeks) to the first day of your last menstrual period. This assumes a 28-day cycle with ovulation on day 14. If your cycle is longer or shorter, your dates may differ. An early ultrasound (6–10 weeks) gives the most accurate EDD and is used to confirm or adjust your date.

Only 5% of babies are born on their due date. 80% of births happen between weeks 38 and 42. Your EDD is a planning target, not a deadline. The Pregnancy Hub has everything you need to prepare.