Pregnancy Due Date Calculator
Last Menstrual Period
How It Works
- LMP: Uses Naegele's Rule (LMP + 280 days). Cycle length adjusts ovulation.
- Conception: Due date = conception + 266 days.
- Ultrasound: Derives LMP from ultrasound date and GA, then calculates EDD.
- IVF: Adjusts embryo age to conception equivalent, then calculates EDD.
Overview
The Pregnancy Due Date Calculator helps you estimate when your baby will arrive using the most common clinical methods: last menstrual period (LMP), conception date, ultrasound measurement, or IVF transfer date. Enter your information to get a precise estimated due date (EDD), your current gestational age, trimester, and important pregnancy milestones. The tool applies Naegele's Rule and clinically accepted pregnancy dating guidelines. All calculations are private and run directly in your browser.
About
About Due Date Calculator
Estimate your pregnancy due date using multiple clinical methods.
Features:
- LMP-based dating (Naegele's Rule)
- Conception date calculation
- Ultrasound-based dating
- IVF/embryo transfer support
- Gestational age tracking
- Trimester identification
- Pregnancy milestones
- Full-term window (37–42 weeks)
- Export to CSV
- Print summary
- 100% private - no data stored
FAQ
How accurate is a due date?
Only about 4–5% of babies are born on their exact due date, but it is a useful clinical estimate.
Is ultrasound more accurate than LMP?
Early ultrasound (7–12 weeks) is often the most precise method for dating a pregnancy.
Can cycle length affect my due date?
Yes. Longer or shorter cycles shift ovulation and therefore conception, affecting the due date.
How does IVF dating work?
IVF pregnancies use embryo age at transfer and count backward to the conception equivalent.
What is the full-term window?
Full-term is 37–42 weeks of pregnancy. Babies born in this range are considered full-term.
Are calculations private?
Yes. All calculations occur in your browser only. No data is stored or transmitted.