Pregnancy Week Calculator

See how far along you are today, in weeks and days.

Dates use your browser’s date picker.
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Due date
Due date
How far along
Trimester
Days to go
Likely conception
Milestones
Work

Saved Calculations

Items you add are saved in this browser.

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How the Due Date Is Estimated

Naegele’s rule counts 280 days (40 weeks) from the first day of the last menstrual period (LMP). This assumes a 28-day cycle with ovulation on day 14; for longer or shorter cycles, the date shifts by the difference.

Due date = LMP + 280 days + (cycle length − 28)   Gestational age = today − LMP

Worked Example

Tips

Only about 4% of babies arrive on their due date; most come within two weeks either side. An early ultrasound is more accurate than LMP dating, and your provider may adjust the date based on it (ACOG). This page is for information only.