Last Updated: August 2026
Not Medical Advice
The information, including but not limited to, text, graphics, images, calculation results, and other material contained on this website are for informational and educational purposes only. No material on this site is intended to be a substitute for professional medical advice, diagnosis, or treatment.
Consult Your Healthcare Provider
Always seek the advice of your physician, obstetrician, midwife, or other qualified healthcare provider with any questions you may have regarding a medical condition, pregnancy dating, or prenatal care. Never disregard professional medical advice or delay in seeking it because of something you have read or calculated on this website.
Calculator Accuracy
While our OB Wheel Calculator utilizes standard obstetric formulas (including Naegele’s Rule) consistent with guidelines established by major medical organizations (such as ACOG), it is inherently a mathematical estimate. True gestational dating often requires early ultrasound evaluation. Furthermore, only a small percentage (approximately 4-5%) of infants are delivered on their exact estimated due date.
No Doctor-Patient Relationship
Use of this website and its tools does not establish a doctor-patient relationship. In the event of a medical emergency, call your doctor or emergency services immediately.