Due Date Calculator
Pregnancy Due Date Calculator
Enter one date and find out when your baby is due — and how many weeks pregnant you are today.
This calculator is a guide only, not a medical calculation. Your doctor or midwife will confirm your dates, usually with an ultrasound.
5.0 ★
from 440+ Google reviews
ASA registered sonographers · 15+ Years Scanning
How is my due date calculated?
Add 280 days — 40 weeks — to the first day of your last menstrual period. That's your due date. Doctors call it Naegele's rule — the same starting point most midwives use. It assumes a 28-day cycle, so your care team may adjust it after your dating scan.
In plain words: pregnancy is counted from the first day of your last period, not from conception. That's why you're already “4 weeks pregnant” around the time you miss a period — the clock started about two weeks before baby did.
How accurate is a due date?
A due date is a best estimate, not a promise. Only about 4 to 5 in every 100 babies arrive on their exact due date. Most babies are born in the window from about two weeks before to two weeks after. Think of your due date as the middle of a due month.
That's normal — cycles vary, ovulation varies, and babies keep their own schedules. Your due date is still useful: it anchors your week count, your trimester dates, and the timing of every scan and check-up along the way.
What if I know my conception date or IVF transfer date?
If you know your conception date, your due date is that date plus 266 days — the same 40 weeks, minus the two weeks before ovulation. If you conceived through IVF, dating is even more precise: count 266 days from egg collection, adjusted for your transfer day (a day-5 transfer adds 261 days from transfer).
Our calculator has modes for both — choose “conception date” or “IVF transfer” instead of last period. IVF mums get the most accurate dates of all — you know the exact start day instead of estimating it.
What happens in each trimester — and which scan suits which weeks?
Pregnancy splits into three trimesters across roughly 40 weeks. The first trimester runs to 13 weeks, the second from 14 to 27, and the third from 28 until birth. Here's the quick map, including when each of our keepsake scans fits best:
| Weeks | Trimester | What's happening | Which scan suits |
|---|---|---|---|
| 4–13 | First | Heartbeat begins; morning sickness peaks and often eases | Reassurance scan from 8 weeks — hear the heartbeat |
| 14–27 | Second | Energy returns; you feel first kicks; anatomy develops fast | Gender scan from 14 weeks |
| 28–40+ | Third | Baby gains weight and chubby cheeks; less room, bigger stretches | 3D/4D face photos — bookable 24–40 weeks, best between 27 and 32 |
When should I book which scan?
Book by your week count, not the calendar:
- From 8 weeks — reassurance scan. A quick look and a listen to the heartbeat, for the weeks when you just want to know all is well.
- From 14 weeks — find out the gender. Our sonographer checks live on screen, and if bub hides the goods, you come back for a free return visit.
- 27–32 weeks — the famous 3D/4D face photos. Chubby cheeks, little yawns, thumb-sucking — the sweet spot when baby has lovely round cheeks but still has room to pose. You can book a 3D/4D scan any time from 24 to 40 weeks; 27 to 32 is simply when the pictures come out best. See real examples in our gallery.
Every option and price is listed on our ultrasound packages page — scans start from $90 (except for the reassurance scan, which is $50) — and you can book online in two minutes with a $20 deposit.
Now you know your dates
See which scan fits which week
Or if you've already picked your week, book your scan — it takes two minutes.