Calculate Your Estimated Due Date
Estimated Due Date:
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Overview
This tool helps expecting parents and healthcare providers estimate the due date for a pregnancy. Calculate the due date by entering either your last menstrual period (LMP) or your conception date. Optionally, adjust for cycle length if it differs from the standard 28 days.
Explanation & Methodology
The Pregnancy Due Date Calculator uses standard obstetric guidelines:
- LMP Method: Due Date = LMP Date + 280 days. If your cycle differs from 28 days, the due date is adjusted by adding the difference (Cycle Length – 28) days.
- Conception Method: Due Date = Conception Date + 266 days.
These formulas are widely accepted in obstetrics to estimate the expected due date.
Example Calculation
For example, if your LMP is January 1, 2025 (with a standard 28-day cycle), the estimated due date would be approximately October 8, 2025.
Frequently Asked Questions
How is the due date calculated?
The due date is calculated by adding 280 days to your LMP (or 266 days to your conception date). If your menstrual cycle length differs from 28 days, the calculation is adjusted accordingly.
What if my cycle is irregular?
If your cycle is irregular, enter your average cycle length in the "Cycle Length" field. The calculator adjusts the due date based on the difference from the standard 28-day cycle.
How accurate is this calculator?
This calculator provides an estimate based on standard guidelines. Actual due dates may vary.