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Due Date Calculator

Estimated due date as LMP + 280 days (Naegele), with gestational age and trimester. Not obstetric care.

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Results

How to use Due Date Calculator

  1. Enter first day of last menstrual period, as of date. Leave a field blank only when the page says the value is missing.
  2. Read the result rows under the form. Errors appear in the status line. Nothing is uploaded.
  3. Treat the figures as formula output, not a diagnosis, diet, pregnancy chart, or care plan.

Due Date Calculator

Naegele 280 days

ComputesEstimated due date as LMP + 280 days (Naegele), with gestational age and trimester. Not obstetric care.
IncludesNaegele 280 days
IncludesGestational age
IncludesTrimester
EnginedateDiff
UploadNone
AdviceInformational only

What Due Date Calculator is

EDD = LMP + 280 days. Gestational age is completed weeks + days from LMP to the as-of date. Trimesters here: first through 13 completed weeks, second 14–27, third 28+.

Informational only. Not a diagnosis, diet plan, pregnancy chart, or medical advice.

The formula runs in this tab. CZNull does not receive the numbers.

How this page computes

Gestational age alone is also gestational age. Ultrasound dating is not applied.

Entities and related jobs

Estimated due date as LMP + 280 days (Naegele), with gestational age and trimester. Not obstetric care. Named features: Naegele 280 days, Gestational age, Trimester.

See also Gestational Age Calculator, Add or Subtract Days, Date Countdown, BMI Calculator, BMR Calculator, TDEE Calculator.

Use cases

A calendar estimate from LMP. Cycles that are not 28 days, IVF, and known conception dates need a clinician.

Not medical advice

Invalid input appears in the status line. IEEE floating point applies unless a row says otherwise. CZNull does not receive the numbers.

Due Date Calculator questions

Does this page upload my numbers?
No. The formula runs in the page you opened. CZNull does not receive the values.
What does Due Date Calculator compute?
EDD = LMP + 280 days.
Why is this its own URL?
Search queries name this job. Nearby modes stay on their own pages so inputs do not mix. Related calculators are linked below Due Date Calculator.
LMP 1 Jan 2026, EDD?
8 Oct 2026 (280 days).
Ultrasound dating?
Not applied.
Is this medical advice?
No. It is arithmetic on the numbers you type. A clinician uses more than a single formula. See the disclaimer.