How is the due date calculated?

Using Naegele's Rule — add 280 days (40 weeks) to the LMP date. There's an adjustment if the cycle differs from 28 days.

Is the due date exact?

No — only ~5% of babies are born on their exact due date. This is an estimate; a doctor's ultrasound can give a more accurate date.

First trimester: week 1-13, Second: week 14-27, Third: week 28-40 (until delivery).

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Enter the date of your last menstrual period (LMP) — instantly find your expected due date and how many weeks pregnant you are now.

Details

Calculate from?

First day of last period

Average cycle length (days)

Result

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Expected Due Date

Current weeks pregnant—

Trimester—

Conception date (estimate)—

Days remaining to due date—