Pregnancy Due Date Calculator
Last updated: July 2026
Estimate a pregnancy due date from the first day of the last menstrual period.
Estimated due date
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- Estimated pregnancy length: —
- Estimated conception date: —
On this page
Quick summary: Estimate a pregnancy due date from the first day of the last menstrual period. Enter the requested values, calculate, review the result, and compare more than one realistic scenario before making a decision.
Read the complete guide
What this calculator does
The Pregnancy Due Date Calculator turns a focused set of inputs into a clear estimate for pregnancy due date. It is intended for quick planning, comparison, and education rather than as an official quote or professional determination. The page runs in your browser and responds immediately, making it practical to test alternatives without rebuilding a spreadsheet. Use the result as a starting point, then compare it with current statements, quotations, policies, measurements, or guidance that applies to your situation.
How the calculation works
Behind the interface, the calculator applies the standard mathematical relationship used for pregnancy due date. Inputs are validated, converted into compatible units when necessary, and combined according to the relevant rate, ratio, date interval, or measurement formula. The displayed result may be rounded for readability. External providers can produce slightly different figures when they use different compounding schedules, day-count conventions, fee rules, thresholds, minimum charges, or rounding methods.
Worked example and scenario testing
Start with values that represent your current pregnancy due date situation and record the first output. Next, create a cautious scenario using a less favorable but plausible assumption. Then create an optimistic scenario that remains realistic. Comparing those three results gives you a range rather than a single fragile answer. A range is often more useful because prices, rates, dates, performance, and personal circumstances can change. Pay special attention to the point at which the result becomes uncomfortable or no longer meets your goal.