About the Pregnancy Due Date Calculator
Estimate your baby's due date from the first day of your last period (adjusted for cycle length), the conception date or an IVF transfer date, and see how many weeks along you are.
Key features
- Due date from last menstrual period, conception date or IVF transfer
- Adjusts for cycle length
- Current week and trimester
- Days to go
- Key pregnancy milestones with dates
- Private: nothing leaves your browser
When is my baby due?
Enter the first day of your last menstrual period (LMP), your conception date or your IVF transfer date to estimate your due date, how far along you are, and when key milestones happen.
How the date is calculated
| Method | Due date |
|---|---|
| Last menstrual period (28-day cycle) | LMP + 280 days |
| LMP with a longer/shorter cycle | LMP + 280 days + (cycle − 28) |
| Conception date | Conception + 266 days |
| IVF day-3 transfer | Transfer + 263 days |
| IVF day-5 transfer | Transfer + 261 days |
Example: LMP on 1 January 2026 with a 28-day cycle → due 8 October 2026. With a 32-day cycle → 12 October 2026.
Trimesters
| Trimester | Weeks |
|---|---|
| First | 1 – 13 |
| Second | 14 – 27 |
| Third | 28 – birth (around 40) |
Common milestones
| Week | Milestone |
|---|---|
| 8–12 | First prenatal visit and dating scan (typical) |
| 13 | End of the first trimester |
| 18–22 | Anatomy (anomaly) scan |
| 24 | Common viability milestone |
| 28 | Third trimester begins |
| 37 | Early term |
| 40 | Estimated due date |
This calculator gives an estimate for information only and is not medical advice. Your doctor or midwife will confirm your due date, usually with an ultrasound.
Related calculators
Count the days with the Date Difference Calculator, or count down with the Countdown Timer.
How to use the Pregnancy Due Date Calculator
- Enter your numbers in the fields above. Units and options can be changed at any time.
- The result updates instantly as you type; there's no calculate button to press.
- Check the breakdown under the main result for the details behind the number.
- Adjust the inputs to compare scenarios, for example a different rate or term.