Pregnancy Due Date Calculator
Women's Health by checkit.health
How is a due date calculated?
The classic method (Naegele’s rule) adds 280 days (40 weeks) to the first day of your last period. We also adjust for cycle length if it isn’t 28 days. Only about 1 in 20 babies actually arrives on the exact due date — it’s an estimate.
Dating scans are more accurate
An early ultrasound dating scan (usually 8–14 weeks) gives a more accurate due date than LMP alone, especially if your cycle is irregular or you’re unsure of your last period. Your maternity team will confirm your dates.
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Educational use only. checkit.health calculators provide general information and are not a medical diagnosis or a substitute for professional advice. Always talk to a qualified healthcare professional about your health, symptoms or before making changes to medication, diet or exercise.
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