Due Date Calculator
Find out when your baby is likely to arrive — and exactly how far along you are today.
Due Date Calculator
Enter the first day of your last menstrual period (LMP). We estimate your due date at 40 weeks.
This is an estimate based on a 28-day cycle. Only about 1 in 20 babies arrive on their exact due date. Your provider's dating scan is the most accurate.
Questions, answered
How is my due date calculated?
We use Naegele's rule: 280 days (40 weeks) added to the first day of your last menstrual period, assuming a regular 28-day cycle.
How accurate is it?
It's a solid estimate, but only about 5% of babies arrive on the exact date. An early ultrasound ('dating scan') is more precise, especially with irregular cycles.
Is my data private?
Yes. If you save your result it stays in your own browser on this device. Nothing is uploaded. Cross-device sync and reminders will be optional with a free account later.
Medical note: This calculator gives an estimate for educational purposes and isn't a substitute for professional prenatal care. Always follow your doctor or midwife's guidance.