Due Date Calculator

Estimate your baby's due date from your last period.

Due Date Calculator

Enter your values and calculate

days

How This Calculator Works

Naegele's rule estimates the due date by adding 280 days (40 weeks) to the first day of your last menstrual period, adjusted for cycle length. Only about 5% of babies arrive on the exact date.

Formula

Due Date = LMP + 280 days (adjusted for cycle length)

Example

An LMP of Jan 1 with a 28-day cycle gives a due date around Oct 8.

Practical Use Cases

  • Pregnancy planning
  • Scheduling ultrasounds
  • Leave planning
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