Pregnancy Due Date Calculator
Free online pregnancy due date calculator using Naegele’s rule. Estimate your due date (EDD) from your last period, conception date, or ultrasound scan. See gestational age, trimester, and milestones. 100% client-side, no signup.
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What is Pregnancy Due Date Calculator?
A Pregnancy Due Date Calculator is a free online tool that estimates your baby’s due date (EDD) using Naegele’s rule — the standard clinical method where the due date is 280 days (40 weeks) from the first day of your last menstrual period (LMP). You can also calculate from your conception date or an ultrasound scan. The tool shows your gestational age, current trimester, days remaining, and key milestones, and supports irregular cycles. All calculations happen 100% in your browser with no data sent to any server.
Key Benefits
- Clinical accuracy using Naegele’s rule, the same 280-day method doctors use
- Three input modes: LMP, conception date, and ultrasound-based dating
- Cycle-length adjustment (21–45 days) for irregular menstrual cycles
- Live gestational age, trimester tracking, and a pregnancy progress bar
- Key milestone dates: end of each trimester, viability, and early full term
Common Use Cases
- •Estimate your due date after a positive pregnancy test using your last period
- •Calculate EDD from a known conception or ovulation date
- •Cross-check an ultrasound dating scan against your LMP-based estimate
- •Track how many weeks and days pregnant you are at any point
- •Plan prenatal appointments around trimester and milestone dates
How to Use the Pregnancy Due Date Calculator
- Choose a calculation method: Select whether to calculate from the first day of your last menstrual period (LMP), your conception date, or an ultrasound scan.
- Enter the date: For LMP, enter the first day of your last period and your average cycle length. For conception, enter the date. For ultrasound, enter the scan date plus the gestational age in weeks and days.
- Click Calculate: Press Calculate to instantly see your estimated due date, gestational age, current trimester, and a pregnancy progress bar.
- Review milestones and copy: Scroll the results to see key milestones (end of trimesters, viability, full term). Use the Copy button to save everything to your clipboard.
Key Features
- Naegele’s rule EDD calculation (280 days from LMP) — the standard clinical method
- Three input modes: last menstrual period, conception date, or ultrasound scan dating
- Cycle-length adjustment (21–45 days) for irregular menstrual cycles
- Live gestational age in weeks and days with a pregnancy progress bar
- Trimester tracking and key milestone dates (viability, full term, trimester ends)
- 100% client-side and private — no health data uploaded, no signup required