Due Date Calculator

Standard obstetric dating: Naegele's rule with cycle-length adjustment.

Start fromDate

Cycle length

days

Only used for LMP mode.

Enter the required values above to see your result.

How the Due Date Calculator works

The calculation follows the standard method used across the US — no shortcuts, no hidden assumptions. Here is exactly what happens behind the scenes:

How does the Due Date Calculator work?

Enter your numbers above and results update instantly using standard formulas, computed entirely on your device.

Is the Due Date Calculator free to use?

Yes — completely free with no signup required, and it works on phones, tablets, and desktops.

Track pregnancy week from LMP, see trimester progress, and confirm the estimated due date.

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Estimate when conception occurred from the due date or last menstrual period, including IVF transfer dates.

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Predict ovulation dates and fertile windows from cycle start and length over coming months.

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