Pregnancy Due Date Calculator

Free pregnancy due date calculator. Enter your last menstrual period or conception date to see your estimated due date, current week, trimester progress, and key development milestones. Includes week-by-week development summaries and important appointment dates.

First Day of Last Menstrual Period

Average Cycle Length (days)

Typical range: 21-35 days. Default is 28.

Enter a date above to calculate your estimated due date and pregnancy timeline.

Medical Disclaimer

This calculator provides an estimate only based on Naegele's Rule. Only about 5% of babies are born on their exact due date. Most deliveries occur within two weeks before or after the estimated due date.

This tool is for informational purposes only and does not constitute medical advice. Always consult your healthcare provider for accurate pregnancy dating, which may include ultrasound measurements and clinical assessment.

How It Works

Naegele's Rule: The due date is calculated by adding 280 days (40 weeks) to the first day of your last menstrual period (LMP), adjusted for your cycle length.

Cycle Length Adjustment: If your cycle is longer or shorter than 28 days, the due date is adjusted accordingly. For example, a 30-day cycle adds 2 extra days.

Conception Date Method: If you know your conception date, we subtract 14 days to estimate the equivalent LMP, then apply Naegele's Rule.

How to Use Pregnancy Due Date Calculator

1Enter your last menstrual period date or conception date.
2View your estimated due date and current week.
3Track trimester progress and upcoming milestones.
4Review week-by-week development information.

Frequently Asked Questions

How is the due date calculated?▾

The due date is calculated as 280 days (40 weeks) from the first day of your last menstrual period (LMP), or 266 days from conception.

How accurate is a due date calculator?▾

Only about 5% of babies are born on their due date. Most are born within 1-2 weeks before or after. Always confirm with your healthcare provider.

What are the three trimesters?▾

First trimester: weeks 1-12. Second trimester: weeks 13-26. Third trimester: weeks 27-40.

About Pregnancy Due Date Calculator

NexTool's Pregnancy Due Date Calculator is completely free to use with no sign-up required. Your data is processed directly in your browser and never sent to our servers, ensuring complete privacy and instant results.