Reverse Due Date Calculator
Reverse Due Date Calculator is a health and wellness calculator that helps you work backwards from a due date to estimate the last period and conception dates. The formula used is: LMP = Due date − 280 days; Conception ≈ Due date − 266 days. Pick the estimated due date.
Rates and fees change frequently. Always confirm the current figures
with the official authority before relying on this result.
Formula
LMP = Due date − 280 days; Conception ≈ Due date − 266 days
- Formula: LMP = Due date − 280 days; Conception ≈ Due date − 266 days
- Pick the estimated due date.
- Based on Naegele's rule and an average 28-day cycle; individual results vary.
Example Calculation
Enter your values and the calculator applies the formula (LMP = Due date − 280 days; Conception ≈ Due date − 266 days) and shows the results below. Change any input to update the result instantly.
Frequently asked questions
What is the Reverse Due Date?
The Reverse Due Date Calculator helps you work backwards from a due date to estimate the last period and conception dates. Pick the estimated due date.
When should I use this calculator?
Use this calculator whenever you need a quick, accurate result for work backwards from a due date to estimate the last period and conception dates.
What should I enter?
Pick the estimated due date.
How accurate are the results?
Results are estimates based on the stated formula and assumptions. Verify against your own figures or an authoritative source before acting on them.
How can I verify the calculation manually?
Apply the formula (LMP = Due date − 280 days; Conception ≈ Due date − 266 days) and work through the numbers step by step. If your result differs, re-check units and rounding first.