Pregnancy Due Date Calculator
All Health & Fitness Calculators
Pregnancy Due Date Calculator: Estimate Baby’s Arrival
How Does a Pregnancy Due Date Calculator Work?
A pregnancy due date calculator estimates your baby’s arrival using key dates and medical data. You may read the blog that explains the science, while this guide focuses on how to use these tools effectively.
3 Methods to Calculate Your Due Date
Our calculator supports LMP date as input for accuracy:
| Method | Formula/Input | Accuracy |
|---|---|---|
| Last Menstrual Period (LMP) | LMP + 280 days (Naegele’s Rule) | ±1–2 weeks |
| Conception Date | Conception date + 266 days | ±3–5 days |
| Ultrasound | Crown-rump length (CRL) measured at 8–12 weeks | ±3–7 days |
Example:
- LMP: January 1 → Due Date: October 8
- Conception: January 14 → Due Date: October 6
Week-by-Week Pregnancy Timeline
Track milestones based on your due date:
| Weeks Pregnant | Key Developments |
|---|---|
| 4–8 | Heartbeat detected, organ formation |
| 12–16 | Gender visible via ultrasound |
| 20–24 | Baby kicks, viability begins |
| 28–32 | Rapid brain growth |
Factors That Affect Due Date Accuracy
- Irregular Cycles: LMP-based calculators may misdate if cycles are >28 days.
- IVF Pregnancies: Use embryo transfer date for precision.
- Multiple Gestation: Twins often arrive 1–4 weeks earlier.
How to Use Due Date Calculators
- Choose Input: Select LMP, conception, or ultrasound date.
- Adjust for Cycle Length: Customize if your cycle is 21–35 days.
- Get Results:
- Estimated due date (EDD).
- Current pregnancy week.
- Trimester timeline.
FAQs
Q: Can my due date change after the first ultrasound?
A: Yes! Early ultrasounds (8–12 weeks) refine EDD by measuring baby’s size.
Q: Does a due date predict labor exactly?
A: No—only 5% of babies arrive on their EDD. Most come 1–2 weeks before or after.
Q: How is IVF due date calculated?
A: Use embryo transfer date + 266 days (or 38 weeks).
Why Trust Our Calculator?
- OB-GYN Approved: Follows ACOG guidelines for LMP and ultrasound inputs.
- Customizable: Adjust for irregular cycles or IVF pregnancies.
- Week-by-Week Tracking: Links to fetal development milestones.
Pair With Our Tools
- Pregnancy Weight Gain Calculator (In dev process)
- Baby Growth Percentile Tool (In dev process)
Final Tip: Recalculate after your first ultrasound for the most accurate EDD. Bookmark your results to share with your healthcare provider!
Read the article: Unlock the Secrets of Pregnancy Due Date Calculation. When Will Your Little One Arrive?