Pregnancy Due Date Calculator

Estimate your due date, current week of pregnancy, and trimester. Choose the calculation method that fits your situation.

Last updated: January 2026

Due Date Calculator

Enter a date to calculate due date.
Note: This tool is a screening aid, not a medical assessment. Results do not constitute medical advice. Consult a healthcare provider for health decisions. Full disclaimer

How due dates are calculated

The most common method uses the first day of your last menstrual period (LMP). Add 280 days (40 weeks) to estimate the due date. This assumes a 28-day cycle with ovulation on day 14. If you know your conception date, the due date is approximately 266 days (38 weeks) from that date.

Only about 5% of babies are born exactly on their due date. A full-term pregnancy ranges from 37 to 42 weeks. This calculator provides an estimate — your healthcare provider will give you the most accurate assessment.

Pregnancy trimesters

Pregnancy is divided into three trimesters: First trimester (weeks 1-13), second trimester (weeks 14-27), and third trimester (weeks 28-40). Each trimester brings different developmental milestones for the baby and different experiences for the mother.

For informational purposes only. Consult your healthcare provider.

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