Pregnancy Due Date Calculator
Pregnancy Due Date Calculator is a health and wellness calculator that helps you estimate a pregnancy due date and current gestational age from the last menstrual period. The formula used is: Due date = LMP + 280 days, adjusted by (cycle length − 28) days (Naegele's rule). Pick the first day of your last menstrual period (LMP) and your average cycle length.
Rates and fees change frequently. Always confirm the current figures
with the official authority before relying on this result.
Formula
Due date = LMP + 280 days, adjusted by (cycle length − 28) days (Naegele's rule)
- Formula: Due date = LMP + 280 days, adjusted by (cycle length − 28) days (Naegele's rule)
- Pick the first day of your last menstrual period (LMP) and your average cycle length.
- An estimate based on Naegele's rule; an ultrasound dating scan is more accurate. About 1 in 20 babies arrive on the exact due date.
Example Calculation
Enter your values and the calculator applies the formula (Due date = LMP + 280 days, adjusted by (cycle length − 28) days (Naegele's rule)) and shows the results below. Change any input to update the result instantly.
Frequently asked questions
What is the Pregnancy Due Date?
The Pregnancy Due Date Calculator helps you estimate a pregnancy due date and current gestational age from the last menstrual period. Pick the first day of your last menstrual period (LMP) and your average cycle length.
When should I use this calculator?
Use this calculator whenever you need a quick, accurate result for estimate a pregnancy due date and current gestational age from the last menstrual period.
What should I enter?
Pick the first day of your last menstrual period (LMP) and your average cycle length.
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 (Due date = LMP + 280 days, adjusted by (cycle length − 28) days (Naegele's rule)) and work through the numbers step by step. If your result differs, re-check units and rounding first.