Pregnancy Due Date Calculator
Calculator ToolsEstimated due date from your last period
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History
All history →Pregnancy Due Date Calculator — at a glance
Estimate your baby’s due date from the first day of your last menstrual period.
Last period: 1 Jan
Run
Due date: 8 Oct
How to use it — step by step
The first day of your last period and your usual cycle length.
1
Enter your values
Fill in the boxes. Sample values are already there so you can see how it works.
2
Calculate
Press the button to get your answer instantly.
3
Read the result
The main answer is shown in a large card with extra details below it.
4
Copy it
Use the copy button to save the result anywhere.
Pro tips
Small things that make the result better.
✦Your doctor may adjust the date after an ultrasound.
✦Most babies are born between 37 and 42 weeks.
✦Use the first day of bleeding, not the last.
Quick facts
Freeno signup, no limit
Instantresult in a moment
Privatenothing is uploaded
Any devicephone, tablet or PC
Frequently Asked Questions
How is the due date calculated?+
Naegele’s rule: add 280 days (40 weeks) to the first day of the last period, adjusted for cycle length.
Is my data safe?+
Yes. Everything runs inside your own browser. Your text, files and images are never uploaded to any server.
Is this tool really free?+
Yes — completely free, no signup, no watermark and no usage limit.
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