About OB Wheel Calculator
Helping expectant mothers and healthcare providers with accurate, accessible pregnancy dating tools — completely free.
Our Mission
OB Wheel Calculator was created with a simple yet powerful mission: to make pregnancy due date calculation accessible to everyone, everywhere. Whether you are an expectant mother eager to know when to expect your little one, or a healthcare provider looking for a quick digital reference, our tool provides instant, reliable results based on established medical formulas.
We believe every expecting parent deserves free access to the same tools used in clinical settings. Our digital obstetric wheel brings the convenience of instant calculation right to your fingertips — no appointments needed, no cost involved, and no personal data stored.
Our Methodology
The OB Wheel Calculator is built on Naegele's Rule, the universally accepted medical formula for estimating pregnancy due dates. This rule, used by obstetricians and midwives worldwide for over 200 years, calculates the Expected Due Date (EDD) by adding 280 days (40 weeks) to the first day of the Last Menstrual Period (LMP).
All content on this website is carefully researched and based on established medical literature. We reference trusted sources including the American College of Obstetricians and Gynecologists (ACOG), peer-reviewed medical journals, and standard obstetric textbooks.
Our gestational age calculations, trimester breakdowns, and milestone charts follow the same standards used in clinical prenatal care to ensure accuracy and consistency.
Our Values
Accuracy
Every calculation is based on Naegele's Rule — the same clinically validated formula used by OB-GYNs worldwide. We ensure our tool reflects the latest medical standards.
Accessibility
Our tool is 100% free, works on any device, and requires no sign-up. We believe pregnancy resources should be available to everyone, regardless of their circumstances.
Privacy
Your privacy matters. All calculations happen in your browser — we never store, transmit, or share your pregnancy data. Your health information stays entirely with you.
Education
Beyond calculations, we provide educational content about pregnancy dating, gestational development, and prenatal care to empower informed decision-making.
Medical Disclaimer
OB Wheel Calculator is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding your pregnancy or a medical condition.