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Pregnancy Due Date Calculator
Estimate a due date from the first day of the last menstrual period, adjusted for usual cycle length.
- Estimated due date
- April 7, 2027
How the calculation works
Due date = first day of the last period + 280 days + (cycle length − 28) days.
Inputs
- First day of last period
- Usual cycle length, days
Calculation details
Dates are approximate and do not confirm pregnancy. A clinician establishes gestational dating using history and ultrasound; IVF requires separate dating.
The adjustment assumes regular cycles and ovulation roughly 14 days before the next period. Actual delivery may occur on another date.
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Updated: 2026-10-02