Pregnancy Calculator

A precise pregnancy calculator that outputs gestational age, due date, and conception date for expectant parents and clinicians.

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About This Tool

Purpose-built pregnancy dating calculator that derives gestational age, conception date, and estimated due date from input data. It accepts either last menstrual period (LMP) plus cycle length or a direct due date, with optional ultrasound-adjusted dating for improved accuracy. Outputs are presented in familiar units and formats to support planning and scheduling. The tool benefits expectant parents, midwives, and clinicians who need fast, auditable dating metrics without manual arithmetic. Core differentiation lies in multiple input modes, transparent calculation steps, and ultrasound-adjusted options that refine accuracy when available. The system emphasizes edge-case handling (irregular cycles, unknown LMP, or future dates) and provides partial results when inputs are incomplete, enabling progressive planning. Use cases include appointment planning, screening windows, and milestone tracking across trimester boundaries. Unique value rests on combining standard obstetric dating rules with flexible input paths and explicit conception-date estimation to support families and care teams in coordinating care.

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How to Use

Provide inputs: LMP_date and/or due_date;
Set cycle_length_days if your cycle differs from 28 days;
Optional: supply ultrasound_adjusted_due_date to refine EDD;
Run calculation;
Review outputs showing gestational age, due date, and conception date.

Frequently Asked Questions

Find Quick Answers

What input should I provide if I don't know my LMP?

If the LMP is unknown, provide a due date and cycle length to estimate GA and EDD; accuracy improves when LMP is known. If both LMP and due date are missing, the tool cannot compute GA reliably.

How accurate are the results?

Results are based on standard obstetric dating rules. Accuracy depends on input correctness. An ultrasound-adjusted due date can improve precision; numbers are for planning and should be confirmed by a clinician for medical decisions.

Does the calculator handle multiple gestations?

The basic calculator assumes singleton pregnancy and does not adjust gestational dating for twins unless an ultrasound-adjusted due date is provided to reflect a refined estimate; outputs otherwise reflect standard dating rules.

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