Evidence-Based Dating

About CalculatePregnancy.com

An independent, calm, and private gestational calculator built on established obstetrical standards.

Our Mission

When learning about a pregnancy, expecting parents are frequently bombarded by advertising-heavy websites, confusing calculators, and alarming claims. CalculatePregnancy.com was built to provide a calm, beautifully designed, and scientifically transparent space to answer fundamental gestational questions without clutter or trackers.

Obstetrical Conventions We Follow

Naegele's Rule (280 Days / 40 Weeks)We date pregnancies from the first day of the last menstrual period (LMP) plus 280 calendar days, with standard cycle-length adjustment modifiers for cycles differing from the traditional 28-day model.

Trimester Boundaries (ACOG / NHS Standards)Following the American College of Obstetricians and Gynecologists (ACOG) and UK National Health Service (NHS) guidelines, our tools group the First Trimester as Weeks 1–13 (days 0–97), the Second Trimester as Weeks 14–27 (days 98–195), and the Third Trimester as Weeks 28–40+ (days 196–280+).

Editorial & Source-Verification Standards

Our developmental milestones, fetal growth estimates, and week-by-week information are compiled from identified authoritative medical and scientific publications: the American College of Obstetricians and Gynecologists (ACOG), the UK National Health Service (NHS), and the INTERGROWTH-21st Project (University of Oxford) for international 50th-percentile fetal weight standards.

All 37 weekly entries carry an editorial status of source_verified, meaning content has been checked against published scientific and clinical literature rather than commercial parenting blogs. This editorial status reflects source alignment and does not constitute clinical review, physician certification, or diagnostic validation. Cited medical sources are referenced for educational context and do not constitute endorsements.

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Medical Notice: CalculatePregnancy.com is an educational and informational tool. It is not clinical diagnostic software and cannot replace the care, ultrasound assessments, or clinical recommendations of your obstetrician, midwife, or certified maternal healthcare provider.

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