Enter your ultrasound date and the gestational age reported on the scan (weeks + days) to get your estimated due date.
Frequently asked questions
How is due date calculated from ultrasound?
EDD = scan date + (280 days − the gestational age reported on the scan). Early ultrasound often provides the most reliable dating.
What if this EDD is different from my LMP-based EDD?
Clinicians often replace LMP dating with early ultrasound dating if they disagree meaningfully. Follow your care team’s assigned EDD.
Does it matter which trimester the scan was done?
First-trimester scans are generally most accurate for dating. Later scans may be used to confirm or adjust.
Can I use CRL (crown–rump length) instead of weeks/days?
This tool uses scan-reported weeks/days. A CRL→GA helper may be added later.