Quick private estimate
Pregnancy date range estimator
Calculate one conventional estimated due date and the wider 37- to 42-week calendar span. Use the result as a question for your maternity or fertility team, not as confirmation of pregnancy or a prediction of labour.
No diagnosisNo saved datesLocal PDF and TXT
A date estimate cannot assess symptoms
Seek prompt local maternity advice for bleeding, severe or persistent pain, severe headache or vision change, fluid leakage, breathing difficulty, or a change in your baby's usual movements. Use emergency services for a life-threatening situation.
Calculate
Enter the date you have
Result
Your estimated calendar range
Read the result as an estimate
The 37- to 42-week span is context, not a safe waiting window. A maternity team should confirm dating and tell you when to seek review.
Privacy
Nothing is remembered
The engine runs locally. The page does not save dates to browser storage, accounts, URLs or analytics. TXT and PDF files are created only after you request them and contain the entered date, so handle them as sensitive health information.
Source check
Formula sources
- NHS due-date calculator - LMP, cycle length, 37-42 week context and scan confirmation.
- ACOG methods for estimating the due date - 280-day convention and day-3/day-5 embryo-transfer offsets.
Sources checked: 26 July 2026.
Important limits
Why not calculate from “conception date”?
Outside documented assisted reproduction, the exact fertilization date is usually uncertain. This route avoids presenting an assumed date as known.
Can a scan change this estimate?
Yes. A maternity professional can compare menstrual history and early ultrasound dating. Use the EDD documented by your care team for clinical decisions.
Does the 42-week date mean it is safe to wait until then?
No. It is only a calendar boundary. Follow your maternity team's monitoring and urgent-care instructions.