Can I calculate from an ultrasound?

Yes. Enter the ultrasound date and the gestational age measured at that time to estimate your due date.

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Pregnancy Calculator

Q: How is the due date estimated?

Typically 280 days (40 weeks) from the first day of the last menstrual period, adjusted for cycle length.

Estimate your pregnancy timeline, trimester, and key milestone dates using one of five methods.

Privacy: All calculations run locally in your browser. We do not send your inputs to any server.

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About This Calculator

This tool estimates your pregnancy timeline based on one of five methods: a known due date, last menstrual period (LMP), ultrasound dating, conception date, or IVF transfer date.

How the calculation works

A typical pregnancy lasts about 280 days (40 weeks) from the first day of the last menstrual period. If your cycle isn't 28 days, the estimate is adjusted. When using a conception date, the tool adds 266 days (38 weeks). For IVF, the embryo age at transfer is factored in.

Milestones shown

The timeline displays key dates including estimated conception, end of each trimester, the anatomy scan window (18–22 weeks), viability milestone (24 weeks), and full term (39 weeks). Past milestones appear dimmed.

Accuracy

Fewer than 4% of births occur on the exact due date, but about 90% happen within two weeks of it. First-trimester ultrasound dating tends to be the most accurate clinical method. This tool provides estimates only — consult your healthcare provider for medical dating.