How is the due date calculated?

With Naegele’s rule: first day of your last period + 280 days, adjusted for your cycle length.

Are weeks counted from conception?

No: they are counted from the first day of your last period, as doctors do (about 2 weeks before conception).

Your due date, how far along you are and the milestones until birth.

I know

DateCycle length (days)

Estimated due date

Thursday, 13 May 2027

Today: 10 weeks + 0 days · Trimester 1

210 days to go40

🍓Baby’s size: about 3 cm

Key dates

An estimate only: your midwife or doctor will date the pregnancy precisely.

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How is the due date calculated?: With Naegele’s rule: first day of your last period + 280 days, adjusted for your cycle length.
Are weeks counted from conception?: No: they are counted from the first day of your last period, as doctors do (about 2 weeks before conception).

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