Ultrasound Due Date Calculator
Projects a surrogate estimated due date from measured gestational age at a dating scan assuming a 40-week clinical model. First-trimester crown–rump length formulas may adjust dates when discrepancy crosses clinical thresholds.
Complete ultrasound timing fields.
Important usage notes & limitations
Reproductive timelines interact with contraception cessation, PCOS phenotype, transgender hormone therapy intensity, low body-fat athletic amenorrhea, and perimenopause. Hormonal contraception intentionally suppresses natural ovulatory signals until washout stabilization — calendar methods become meaningful only once cycles resume reliably.
See also: Pregnancy Due Date Calculator · Women's health calculators hub.