Due Date Calculator
Estimated due date from LMP with cycle adjustment.
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Estimated due date
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Today you are
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Days remaining
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Trimester
Naegele’s rule: 280 days from the LMP, shifted by your cycle length vs the standard 28. Dating scans can move the estimate a week or two either way — the scan result is the one clinicians trust most.
How to use the Due Date tool
- Enter your due date in the fields above.
- Adjust any slider or type an exact number — the answer updates as you go.
- Copy the result and close the tab. Nothing you entered was sent anywhere.
About the Due Date tool
Standard Naegele’s rule (280 days from the first day of the last period) adjusted for your cycle length, and shows the current gestational week and trimester.
Only the baby knows the real date — first pregnancies average about 4 days past this estimate, so treat it as a window, not an appointment.
Everything runs locally in your browser: no data is uploaded, no account is needed, and it works offline once the page has loaded.
Embed this tool
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