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Due Date Math: How Pregnancy Is Dated

Only ~4% of babies arrive on their due date — Naegele's rule, scan dating and the real arrival-week odds.

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Due Date Calculator (LMP / Naegele)

Estimated due date from your last period with cycle-length adjustment — plus what 'due date' statistically means.

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Pregnancy Week Calculator (How Far Along?)

Exactly how many weeks-and-days pregnant you are today, from LMP or due date, with trimester placed.

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Trimester Calculator (Exact Dates)

Your personal first/second/third trimester boundary dates from LMP or EDD.

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Due Date from Ultrasound (CRL)

Gestational age and EDD from crown-rump length using the Robinson–Fleming dating curve.

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Birth Date Probability Calculator

The real arrival-date distribution around your EDD — week-by-week odds instead of one misleading date.

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Reverse Due Date Calculator (When Did I Conceive?)

Work backwards from a due date or birth date to the likely conception window.

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