Conception Date Calculator: Track Pregnancy Timeline & Milestones
A simple calculator that determines a baby's likely conception date based on the due date or last menstrual period, helping parents understand their pregnancy timeline and important gestational milestones.
Conception Date Calculator
Calculate your estimated conception date and due date based on your last menstrual period. Get a range of possible conception dates and important pregnancy milestones.
Calculate Your Dates
A typical menstrual cycle is 28 days, but can range from 21 to 35 days
Your Results
Estimated Conception Window
Estimated Due Date
Current Week of Pregnancy
Current Trimester
Next Pregnancy Milestone
How to Use
- Enter the first day of your last menstrual period
- Select your average menstrual cycle length
- Click Calculate to see your results
- Review your conception window and important dates
Important Pregnancy Dates
First Trimester: Weeks 1-12
Missed Period (4 weeks)
First Ultrasound (8 weeks)
End of First Trimester (12 weeks)
Second Trimester: Weeks 13-26
Anatomy Scan (20 weeks)
Viability (24 weeks)
Third Trimester: Weeks 27-40
Third Trimester Begins (28 weeks)
Full Term (37 weeks)
Due Date (40 weeks)
Frequently Asked Questions
The conception date is typically estimated to occur 14 days before ovulation in a regular 28-day cycle. We calculate a window of possible conception dates based on your cycle length and last menstrual period.
This calculator provides an estimate based on average cycle lengths and typical conception patterns. Individual variations in ovulation and cycle length can affect actual conception dates. For medical accuracy, consult your healthcare provider.
If your cycles are irregular, the calculator may be less accurate. It's best to use an average of your cycle lengths over the past few months. Consider tracking your cycles and consulting with a healthcare provider for more precise dating.
The due date is calculated using Naegele's rule, which adds 280 days (40 weeks) to the first day of your last menstrual period. This method is commonly used by healthcare providers for initial due date estimation.