Pregnancy Calculator
First day of your last menstrual period
Default is 28 days. Typical range: 20-40 days.
How It Works
- Due Date: Calculated using Naegele's Rule (LMP + 280 days), adjusted for your cycle length
- Conception Date: Estimated as cycle length - 14 days from LMP
- Fertile Window: Typically 5 days before conception to 1 day after
- Gestational Age: Measured from the first day of your last menstrual period
- Trimester: 1st (0-13 weeks), 2nd (14-27 weeks), 3rd (28+ weeks)