The OB Wheel Calculator is a versatile pregnancy tool used to calculate important pregnancy dates such as the estimated due date (EDD), gestational age, and conception date. It can work from various reference points including the last menstrual period (LMP), ultrasound data, or known conception dates. This digital tool replicates the traditional OB wheel’s functions and often includes additional features like accuracy for leap years and combining multiple methods for better estimations. It streamlines pregnancy care by providing quick and reliable calculations for expectant mothers and healthcare professionals.
OB Wheel Calculator
Results
Estimated Date of Conception
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Estimated Due Date (EDD)
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Current Gestational Age
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Trimester
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Notes & Interpretation
Naegele’s rule used for EDD: EDD = LMP + 280 days. Conception estimated as LMP + (cycle – 14) + 14 days ≈ LMP + (cycle – 28) + 14 days (default cycle 28 → conception ≈ LMP + 14 days).