About this Calculator
Conception is the biological process of sperm fertilizing an egg. This tool estimates the probable window of conception.
Formula & Calculations
Mathematical Formula
Conception = Due Date - 266 Days
Calculated range is +/- 3 days around the estimated conception date.
How to Calculate Step-by-Step
1
Select mode
Based on Due Date vs LMP.
2
Enter date
Input anchor date parameters.
3
Subtract offset
Deduct 266 days from Due Date.
How to Use & Best Practices
Select Due Date or LMP and enter your dates.
Frequently Asked Questions
Can I find the exact day I conceived?
Sperm can survive in the reproductive tract up to 5 days, so exact day is hard to pin down.