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OB Wheel Pregnancy Calculator

Calculate your estimated due date, current gestational age, and pregnancy milestones using the standard OB wheel method.

Medical Disclaimer

This tool is provided for educational and informational purposes only. The calculators do not constitute medical advice, diagnosis, or treatment. Always consult a qualified health professional regarding any medical conditions.

OB Wheel Input

How to Use the OB Wheel Calculator

An OB Wheel (Obstetric Wheel) is a tool used by medical professionals to calculate pregnancy due dates and track milestones based on LMP, Ultrasound, or a known Due Date.

  • Select your calculation method (LMP, Ultrasound, or Due Date).
  • Enter the required dates and gestational age if applicable.
  • Results are processed instantly in your browser.

Mathematical Formulas

The underlying calculations rely on the standard Naegele's rule approximation of 280 days (40 weeks):

Estimated Due Date = LMP + 280 Days