Pregnancy Due Date Calculator
Calculate your estimated due date based on your last menstrual period or conception date.
Disclaimer
This calculator provides estimates for general information purposes only. Results are based on standard formulas and may not reflect your individual circumstances. Always consult a qualified professional for advice specific to your situation.
Frequently Asked Questions
How accurate is a due date calculator?
What are the trimesters of pregnancy?
What is Pregnancy Due Date?
A pregnancy due date calculator (also called an estimated date of delivery or EDD calculator) predicts when your baby is likely to be born based on the first day of your last menstrual period or your conception date.
How this calculator works
Using the LMP method, the calculator adds 280 days (40 weeks) from the first day of your last period — this is the standard Naegele's rule used by doctors worldwide. Using the conception date method, it adds 266 days (38 weeks). The progress bar shows which trimester you're in (1st: weeks 1-12, 2nd: weeks 13-26, 3rd: weeks 27-40), and the milestone timeline marks key dates including the 12-week scan, 20-week anatomy scan, and full term at 36 weeks. Only about 5% of babies arrive on their exact due date.
Naegele's Rule (LMP Method)
Standard EDD calculation: first day of last menstrual period + 280 days. Assumes a regular 28-day cycle with ovulation on day 14. Adjustments needed for: longer/shorter cycles (subtract 7 days, add cycle length), known conception date (more accurate), IVF (use embryo transfer date + 266 days for fresh embryos).
Key Pregnancy Milestones
WEEK 8-12: Dating scan (confirms EDD, viability). WEEK 11-13: NIPT/combined screening for chromosomal conditions. WEEK 18-22: Detailed anatomy scan. WEEK 28: Glucose tolerance test (gestational diabetes screening). WEEK 36: Birth plan discussion. WEEK 37: Considered full term in Australia. WEEK 40: Estimated due date. WEEK 41-42: Most providers recommend induction.
How Accurate Are Due Dates?
Only 5% of babies arrive on their exact EDD. ~50% arrive within 1 week either side. 80% arrive within 2 weeks. The 'normal' delivery window: 37-42 weeks. First-time mums often deliver 5-7 days after EDD on average. Subsequent pregnancies trend slightly earlier. Dating scans before 12 weeks are typically more accurate than LMP-based dates.
Australian Antenatal Care
Public system (Medicare-covered): shared care between GP and public hospital, midwife-led models, public hospital obstetrics. Private system: private obstetrician + private hospital ($3k-$10k out-of-pocket typical). All states offer 5-day public midwifery + paid parental leave (22 weeks NMW from 2025-26, indexed).
All calculations are performed in your browser — your data never leaves your device. Results are for general guidance only and should not be considered professional financial advice.
Built and maintained by Konstantin Iakovlev. Data sourced from the ATO and official Australian government sources.