Estimated Due Date (EDD)
Estimated due date from LMP (Naegele's rule).
RESULT
Estimated Due Date (EDD)
What is Estimated Due Date (EDD)?
Estimated due date from LMP (Naegele's rule). Estimated Due Date is intended for use in: Pregnant patients.
How to Use the Estimated Due Date Calculator
- Enter Last menstrual period (LMP) date. Enter as YYYY-MM-DD
- Enter Average cycle length (optional) in days. Defaults to a standard 28-day cycle
- Click Calculate to see your result and interpretation.
Formula & Version
This calculator uses formula version 1.0, last reviewed September 2026.
Clinical Considerations & Limitations
- Assumes a regular cycle and certain LMP date — an early first-trimester ultrasound is more accurate when LMP is uncertain or cycles are irregular.
References
- Naegele FC, 1812 (classic rule: LMP + 280 days)
Frequently Asked Questions
What is Estimated Due Date (EDD)?
Estimated due date from LMP (Naegele's rule).
Who is Estimated Due Date intended for?
Pregnant patients. Always confirm applicability to your specific patient before use.
What are the limitations of Estimated Due Date?
Assumes a regular cycle and certain LMP date — an early first-trimester ultrasound is more accurate when LMP is uncertain or cycles are irregular.
What formula or reference does Estimated Due Date use?
Naegele FC, 1812 (classic rule: LMP + 280 days)
Is Estimated Due Date a diagnosis?
No. Estimated Due Date produces a score or estimate to support clinical decision-making — it is not a diagnosis and should be interpreted alongside full clinical judgement.
Medical Disclaimer: Medical calculators are provided for informational and educational purposes only. Results should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always verify results with a qualified healthcare professional.
