Due Date Calculator
When is my
baby due?
Enter the first day of your last menstrual period to estimate your due date and current week of pregnancy.
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Due Date Ledger
Results update instantly as you type
Estimated Due Date
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Current Week
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How is this calculated?
We use Naegele's Rule, the most widely used method: adding 280 days (40 weeks) to the first day of your last period. This assumes a 28-day cycle, so your actual due date based on ultrasound may differ by a few days.
A note of caution
This is a reference estimate. Please confirm your due date with an ultrasound at your OB-GYN.
Frequently Asked Questions
How accurate is this result?
It's based on a standard obstetric formula, but ultrasound dating is more precise.
Is my data stored or sent anywhere?
No. All calculations happen entirely in your browser.
Does this work on mobile?
Yes, the layout automatically adapts to your screen size.