Ultrasound Due Date Calculator
Calculate your due date, conception date, and current pregnancy week using ultrasound results
Enter Ultrasound Data
Calculation Method
Due Date = Ultrasound Date + (280 days - Gestational days at scan)
Standard pregnancy is 280 days (40 weeks)
Calculation Results
Enter Data to View Results
Input your ultrasound date and gestational age to calculate
Frequently Asked Questions
How accurate is an ultrasound due date calculator?
Ultrasound due date calculators are highly accurate, especially when based on first-trimester scans (before 12 weeks). Early ultrasounds have a margin of error of just ±5 days, making them the most reliable method for determining due dates.
How is due date calculated from ultrasound?
Due date = Ultrasound date + (280 days - Gestational days at scan). Standard pregnancy duration is 280 days (40 weeks). Subtract the gestational age at scan and add to the ultrasound date.
Which is more accurate: ultrasound due date or last menstrual period (LMP)?
Ultrasound due dates are more accurate than LMP estimates, especially for women with irregular cycles or uncertain last period dates. Ultrasound directly measures fetal development.
Why do doctors trust ultrasound due dates more?
Doctors prefer ultrasound dating because it directly reflects actual fetal development. First-trimester crown-rump length (CRL) measurement is the gold standard for pregnancy dating with minimal error.