Pregnancy Due Date Calculator

Free pregnancy due date calculator. Enter your last menstrual period (LMP) to calculate your estimated due date, current week, and trimester. Use our free calcu

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Estimated Due Date hesaplanacak
Current Week hesaplanacak
Trimester hesaplanacak
Days Until Due Date hesaplanacak

How Is a Due Date Calculated?

A full-term pregnancy is approximately 40 weeks (280 days) from the first day of the last menstrual period (LMP). This is known as Naegele's rule — the standard method used by most healthcare providers worldwide.

Naegele's Rule

Estimated Due Date (EDD) = Last Menstrual Period + 280 days

Alternatively: EDD = LMP + 9 months + 7 days

Example: LMP = January 1 → EDD = October 8

Pregnancy Trimesters

TrimesterWeeksKey Developments
First trimester1–12Organ formation, morning sickness common
Second trimester13–26Movement felt, anatomy scan at 20 weeks
Third trimester27–40Rapid growth, preparation for birth

Important Notes

  • Only 4% of babies are born on their exact due date.
  • A normal delivery window is 37–42 weeks.
  • Ultrasound dating (especially at 8–12 weeks) is more accurate than LMP for irregular cycles.
  • Always confirm your due date with your healthcare provider.

If Your Cycle Is Not 28 Days

Naegele's rule assumes a standard 28-day cycle. If your cycle is shorter or longer, ovulation and conception shift accordingly. Some calculators allow cycle length adjustment for a more personalized estimate.

How to Use This Calculator

Using our calculator is simple: enter the required values into the input fields and click the calculate button. Results are displayed instantly on screen. You can adjust the values and recalculate to compare different scenarios and find the best option for your situation.

Frequently Asked Questions

QuestionAnswer
How accurate are the results?We use standard formulas and up-to-date 2025 rates. Individual circumstances may vary slightly.
Is this calculator free?Yes, completely free and no registration required.
What should I do for exact figures?For precise information, consult a relevant professional or official authority.
Does it work on mobile devices?Yes, it works seamlessly on all devices and screen sizes.

Important Notes

This calculator is provided for informational purposes only. For legal, financial, or medical decisions, always seek advice from qualified professionals. Calculation results do not constitute official documents. Legislative changes may affect results; please visit the relevant official website for the most up-to-date information. Our calculators are regularly updated to reflect current regulations and rates.

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Frequently Asked Questions

The standard method (Naegele's rule) adds 280 days (40 weeks) to the first day of your last menstrual period, adjusted for your cycle length.
Only about 5% of babies are born on their exact due date. The normal delivery window is 37-42 weeks. Ultrasound in the first trimester gives the most accurate estimate.
First trimester: weeks 1-12. Second trimester: weeks 13-26. Third trimester: weeks 27-40. Full term is considered 37-40 weeks.