Conception Calculator
Estimate conception date, due date, gestational age, and trimester from LMP or expected due date.
Conception & Pregnancy Details
What is a Conception Calculator?
A conception calculator estimates the date of conception and key pregnancy milestones using either your last menstrual period or your expected due date. It helps determine gestational age and current trimester.
How to Use This Calculator
- Select whether you know your LMP or your due date.
- Enter the known date in the appropriate tab.
- Click Calculate to see conception estimates and pregnancy progress.
Frequently Asked Questions
How is conception date calculated?
Conception is estimated as LMP plus 14 days, assuming a 28-day cycle. If using a due date, conception is estimated as due date minus 266 days.
What is gestational age?
Gestational age measures how far along the pregnancy is, counted from the first day of the last menstrual period. It is typically expressed in weeks and days.
Why does the due date differ from conception plus 9 months?
Pregnancy is measured as 40 weeks (280 days) from LMP, but conception occurs about 2 weeks after LMP. Therefore, the interval from conception to due date is approximately 266 days.
Can I use this for irregular cycles?
This calculator assumes a standard 28-day cycle. If your cycles are significantly longer or shorter, the conception estimate may be off by several days.