Conception Date Calculator: From Due Date or Last Period
Work backwards to ovulation, the fertile window and conception.
Pregnancy Due Date Calculator
LMP or conception date.
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About Pregnancy Due Date Calculator
Enter last period or conception date for due date, trimester, and week count.
📐 Methodology & Reference Accuracy:
Calculations, formulas, and conversions execute locally in your web browser. Output models are benchmarked against official reference standards and updated for 2026.
🔒 This tool runs entirely in your browser. Nothing is uploaded or stored.
Background reading: Pregnancy Due Date on Wikipedia. More: all calculators.
Frequently Asked Questions about Pregnancy Due Date Calculator
How do I use the Pregnancy Due Date Calculator?
Open the Pregnancy Due Date Calculator and use the controls in the workspace below: lmp or conception date. Results appear instantly in your browser, with nothing to install, sign up for, or pay for.
Is the Pregnancy Due Date Calculator free?
Yes. The Pregnancy Due Date Calculator is completely free, like every tool in the PrimeFreeTools library. There are no accounts, subscriptions, or usage limits.
Does the Pregnancy Due Date Calculator store or share my data?
No. The Pregnancy Due Date Calculator runs with JavaScript in your browser, so what you enter never leaves your device and nothing is stored on a server.
What can I use the Pregnancy Due Date Calculator for?
Enter last period or conception date for due date, trimester, and week count. You will find it grouped under Calculators together with 116 other free tools on the PrimeFreeTools homepage.
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