Health & Fitness Calculators
Pregnancy Conception Calculator
Estimate the conception date from a due date.
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About the Pregnancy Conception Calculator
Working backward from a due date, this calculator estimates when conception likely occurred — about 266 days before the due date — along with the corresponding last-period date and fertile window. It's helpful for understanding a pregnancy's timeline or answering 'when did I conceive?'.
How to use the Pregnancy Conception Calculator
- 01Enter your estimated due date.
- 02Read the result instantly — it recalculates as you type.
- 03Adjust the numbers to model different scenarios.
Frequently asked questions
How is conception date estimated?
Roughly 266 days before the due date (or ~14 days after the last period start). It's an estimate — actual conception timing varies.
Can it be exact?
No — sperm can survive several days, so conception can happen a few days after intercourse. The result is a best estimate.