When will yourlittle onearrive?
Find your estimated due date, see how far along you are, and follow every milestone of your 40-week journey — reviewed by Stepcare's obstetricians.
40
weeks of pregnancy
4%
babies born on their due date
4
ways to calculate
Calculate based on
The maths behind it
How due dates are calculated
Doctors count pregnancy from the first day of your last period, not from conception — so you are already “2 weeks pregnant” on the day you conceive. Each method below simply works back to that same starting point.
From your last period
LMP + 280 days
Naegele's rule. We also adjust for cycles shorter or longer than 28 days.
From conception
Conception + 266 days
38 weeks from fertilisation. Useful if you tracked ovulation closely.
From IVF transfer
Transfer + 266 − embryo age
Day-5 transfer: +261 days. Day-3 transfer: +263 days. Very precise.
From an ultrasound
Scan date + (280 − age on scan)
The most accurate method when the scan is done before 14 weeks.
Trimester guide
What to expect, and when
01
First trimester
Weeks 1–13
- Confirm pregnancy & start folic acid
- Dating scan (7–9 weeks)
- NT screening (11–13 weeks)
- Morning sickness usually peaks
02
Second trimester
Weeks 14–27
- Anomaly scan (18–22 weeks)
- Feel first movements (18–22 weeks)
- Glucose tolerance test (24–28 weeks)
- Energy and appetite return
03
Third trimester
Weeks 28–40
- Growth scans & blood pressure checks
- Tdap vaccine (27–36 weeks)
- Birth plan & hospital bag (36 weeks)
- Full term from 37 weeks
Good to know
Frequently asked questions
Pregnancy is counted as 40 weeks (280 days) from the first day of your last period, adjusted for your cycle length. If you know your conception or IVF transfer date, we count 266 days from fertilisation instead, which is often more precise.
This calculator gives an estimate only. Your obstetrician will confirm your due date after your dating scan. It is not a substitute for medical advice.