Parenting
Pregnancy Calculator
Due date & milestones
Calculate your estimated due date, current week, and trimester based on the first day of your last menstrual period.
Dates
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How It Works
The Formula
EDD = LMP + 280 days (Naegele's rule)
LMP = first day of last menstrual period
Worked Example
LMP January 1
- 1Jan 1 + 280 days
- 2EDD = October 8
Result: Due October 8 · ~40 weeks
Pro Tip
Only ~4% of babies arrive exactly on the due date — it's a window.
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Calculatore.net Team
Our team of finance and math specialists builds every calculator with industry-standard formulas, then verifies each tool hands-on. Learn more in our blog & guides.