Pregnancy Week Calculator
Estimate current pregnancy week, pregnancy day, trimester, due date, and days remaining from pregnancy dates.
Disclaimer: This calculator provides educational estimates only. It is not medical advice, diagnosis, contraception guidance, or a substitute for a qualified healthcare professional.
Pregnancy Week Calculator
A pregnancy week calculator estimates current gestational week and day from pregnancy dating information. It helps translate a date such as last period or due date into week, day, trimester, and days remaining.
The pregnancy week calculator is included in the fertility and pregnancy timing cluster as a next step after a due date estimate.
How to Use the Pregnancy Week Calculator
- Enter the pregnancy dating information requested by the page.
- Review the estimated week and day.
- Check trimester and due date context.
- Use the result as a general timing estimate.
Formula Used
Gestational age days = today - estimated LMP
Pregnancy week = floor(gestational age days / 7)
Pregnancy day = gestational age days modulo 7
Estimated LMP from due date = due date - 280 days
This calculation uses gestational dating, which starts from the first day of the last menstrual period.
Example
If estimated LMP was June 1, 2026 and today is June 22, 2026, gestational age is 21 days, or 3 weeks and 0 days.
What Your Result Means
Pregnancy week is a dating estimate used for general timing. Clinical dating may differ when ultrasound or other medical information is available.
Accuracy and Limitations
Pregnancy dating can vary if periods are irregular, ovulation occurred later than expected, or the due date was adjusted by a clinician. Use professional care for medical decisions.
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Methodology and Disclaimer
This calculator uses gestational-age date math. It provides educational estimates only. It is not medical advice, diagnosis, contraception guidance, or a substitute for a qualified healthcare professional.
FAQ
What does pregnancy week mean?
Pregnancy week usually means gestational week counted from the first day of the last menstrual period.
Why is pregnancy counted before conception?
Gestational dating uses LMP because it is often easier to identify than the exact conception date.
Can ultrasound change pregnancy week?
Yes. A clinician may adjust dating based on ultrasound and clinical context.
What trimester is week 14?
Week 14 is generally the start of the second trimester.
Is this calculator a medical tool?
No. It provides educational timing estimates only.