Pregnancy Due Date Calculator
Estimate your due date and current pregnancy week.
Last updated: January 2025 · Built for the 2024–25 financial year
Inputs
Results
Estimated due date
16 December 2026
Pregnancy weeks
8 weeks
Trimester
First
Results are estimates only. For financial advice, consult a licensed adviser.
Overview
Estimated due date by Naegele's rule + LMP
Pregnancy is dated from the first day of the last menstrual period (LMP), even though conception occurs around two weeks later. Naegele's rule estimates a 280-day (40-week) gestation by adding 7 days then subtracting 3 months from LMP.
Only about 4% of babies arrive on the due date. Term is anywhere between 37 and 42 weeks. Ultrasound dating in the first trimester is more accurate than LMP if cycles are irregular.
Formula
Naegele's rule
EDD = LMP + 7 days − 3 months (or LMP + 280 days)
Trimester milestones
| Week | Milestone |
|---|---|
| 12 | End of first trimester — risk drops sharply. |
| 20 | Halfway; morphology scan. |
| 24 | Glucose tolerance test for gestational diabetes. |
| 28 | Anti-D injection if Rh-negative. |
| 37 | Considered full-term. |
| 40 | Estimated due date. |
Pro tips
- •Take folate 3 months pre-conception and through trimester 1.
- •Confirm dates with first-trimester ultrasound for accuracy.
- •Eligible Australian parental leave: 22 weeks (FY26).