BMITool · Free health calculator

Pregnancy Due Date Calculator: Estimate Delivery Date

Estimate your pregnancy delivery date, current gestational week, and key developmental milestones using standard obstetric conventions.

Calculation methods

Calculate using the first day of your last menstrual period (Naegele rule: LMP + 280 days), known conception date, or first-trimester ultrasound measurements.

Due date vs delivery date

Only about 4 to 5 percent of babies arrive on their exact calculated due date. Most full-term births occur between 37 and 42 gestational weeks.

Ultrasound adjustments

First-trimester crown-rump length (CRL) sonograms provide the gold standard for clinical confirmation if your menstrual cycle is irregular.