Women's health literacy
Pregnancy due date estimate
LMP-based educational dating only. Confirm pregnancy care and dating with your obstetric clinician.
Choose the first day of your last period.
What this result means
This educational due-date estimate uses a common last-menstrual-period (LMP) method often summarized as about 280 days (40 weeks) from the first day of the last period.
Only a small share of babies arrive on the exact due date. Dating ultrasound and obstetric care provide clinical dating — this tool does not replace prenatal care.
How we calculate it
- Estimated due date ≈ first day of last menstrual period + 280 days (Naegele-style educational approach).
- We also show an estimated gestational age window based on today’s date when LMP is provided.
Limitations
- Irregular cycles, uncertain LMP, recent hormonal contraception, breastfeeding, and fertility treatments change accuracy.
- Not a pregnancy test and not prenatal care.
- Seek obstetric care for confirmation, screening, and warning-symptom guidance.
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Sources / References
Educational estimate only — not diagnosis, treatment, or medication dosing. See our medical disclaimer and editorial policy.