Estimate your due date and find your fertile window and ovulation day from your cycle.
Estimate your due date from your last period, conception, or ultrasound.
CalculatorFind your fertile window, ovulation day, and next period from your cycle.
A plain-language look at Naegele's rule, ultrasound dating, and why your estimated due date is an estimate rather than a deadline.
How the menstrual cycle, ovulation timing, and the roughly six-day fertile window fit together, and what the science does and does not tell you.
This tool is for general informational and educational purposes only and is not medical advice. It does not diagnose, treat, or replace care from a qualified professional. Always consult a physician or other qualified healthcare provider about your individual health.