Pregnancy due date calculator
Weeks of pregnancy and estimated due date.
Weeks of pregnancy.
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Pregnancy due date calculator: what it is for
The pregnancy calculator shows how many weeks along you are, the trimester and the estimated due date, from the first day of your last menstrual period (LMP).
It is an estimate: an ultrasound and your prenatal care give the most accurate date.
How to use
- Enter the first day of your last period.
- See the weeks, the trimester and the due date.
- Follow your pregnancy week by week.
When to use it
- Know how far along you are.
- Plan for the baby's arrival.
- Check the estimated due date.
Frequently asked questions
How is the due date calculated?
With Naegele's rule: 280 days (40 weeks) after the first day of the last menstrual period. The date from an ultrasound is usually more accurate.
Is it really free?
Yes, 100% free. No sign-up, no subscription and no usage limits. All Tools123 tools are free and run right in your browser.