Pregnancy Due Date Calculator
The Pregnancy Due Date Calculator estimates your baby's due date using Naegele's rule, based on either your last menstrual period or a known conception date.
Advertisement
Advertisement
How This Tool Works
Choose whether you know your last menstrual period or your conception date, enter that date, and get your estimated due date and current gestational age.
Formula & Method
Naegele's rule: due date = last menstrual period + 280 days, or conception date + 266 days.
Example Calculation
A last menstrual period of January 1 gives an estimated due date of October 8 — 280 days later.
Frequently Asked Questions
How accurate is Naegele's rule?+
It's a widely used estimate, but only about 5% of babies are born exactly on their calculated due date — most arrive within two weeks before or after.
What if my cycle isn't exactly 28 days?+
Naegele's rule assumes a 28-day cycle. If yours is longer or shorter, your actual due date may shift — an ultrasound dating scan is more precise for irregular cycles.
Should I confirm this with my doctor?+
Yes — this is an estimate for planning purposes only. Your healthcare provider will confirm your due date using clinical measurements and ultrasound dating.
Advertisement
Related Tools
Age Calculator
Calculate your exact age in years, months, and days.
Use tool →Everyday ToolsDate Difference Calculator
Calculate the number of days, weeks, or years between two dates.
Use tool →HealthIdeal Weight Calculator
Estimate a healthy weight range based on your height and sex.
Use tool →HealthBMI Calculator
Calculate your Body Mass Index and see your weight category.
Use tool →