days
Estimated due dateSat, May 22, 2027
You are 11 weeks and 3 days pregnant today.
TrimesterFirst
Days to go200
Likely conceptionSat, Aug 29, 2026
Progress28.6%
● calculated in 0.60 msruns in your browserupdated 07:35:35
Visualise
How far along you are
Breakdown
Your pregnancy timeline
| Week | What happens | Date |
|---|---|---|
| Week 4 | Pregnancy test can show positive | Sat, Sep 12, 2026 |
| Week 8 | First scan and booking visit | Sat, Oct 10, 2026 |
| Week 13 | Second trimester starts | Sat, Nov 14, 2026 |
| Week 20 | Anatomy scan (week 18–22) | Sat, Jan 2, 2027 |
| Week 27 | Third trimester starts | Sat, Feb 20, 2027 |
| Week 37 | Full term begins | Sat, May 1, 2027 |
| Week 40 | Estimated due date | Sat, May 22, 2027 |
The maths
Formula
This is the exact calculation the tool runs.
Due date = First day of last period + 280 days + (cycle − 28)
280 days40 weeks
CycleDays from one period to the next
ConceptionAbout 14 days after period
Practice
Worked examples
Click "Try it" to load an example into the tool.
28-day cycle
First day of last period: Mon, Jun 1, 2026Average cycle length: 28 days
Mon, Mar 8, 2027
Longer 32-day cycle
First day of last period: Thu, Sep 10, 2026Average cycle length: 32 days
Mon, Jun 21, 2027
Early pregnancy
First day of last period: Mon, Oct 5, 2026Average cycle length: 28 days
Mon, Jul 12, 2027
Step by step
How to use the Pregnancy Due Date Calculator
Pick the first day of your last period
Not the last day. If unsure, use your best guess.
Enter your cycle length
Most cycles are 28 days. Change it if yours is longer or shorter.
See your dates
Your due date, current week and key milestones appear instantly.
Questions
Frequently asked questions
How accurate is the due date?
Only about 4% of babies arrive on the exact date. Most are born within two weeks either side.
Can a scan change my due date?
Yes. An early ultrasound is often more accurate, and your doctor may update the date.
What is Naegele’s rule?
The standard method: add one year, subtract three months and add seven days to the first day of your last period.