Pregnancy Due Date Calculator: Find Your Due Date
Free online pregnancy due date calculator and web app. Find your due date from your last period, conception date, IVF transfer or ultrasound, and see how many weeks pregnant you are. Install it on your phone like an app.
How the due date is calculated
A full pregnancy lasts about 40 weeks (280 days) counted from the first day of your last menstrual period (LMP). Naegele's rule adds 280 days to that date, and adjusts for your cycle length if it is not 28 days. This calculator also works from your conception date, IVF embryo transfer or an ultrasound.
Due date methods
| Method | How it works |
|---|---|
| Last menstrual period | LMP + 280 days, adjusted for cycle length |
| Conception date | Conception + 266 days |
| IVF day 5 transfer | Transfer date + 261 days |
| IVF day 3 transfer | Transfer date + 263 days |
| Ultrasound | Scan date + (280 days minus gestational age at the scan) |
Pregnancy trimesters
| Trimester | Weeks |
|---|---|
| First | Week 1 to week 13 and 6 days |
| Second | Week 14 to week 27 and 6 days |
| Third | Week 28 until birth |
Why your due date is only an estimate
Only about 4 to 5 percent of babies are born on their exact due date. Most arrive in the window between 37 and 42 weeks. Your doctor or midwife may adjust your due date after an early ultrasound.
Important
This calculator is for general information and is not medical advice. Always follow the advice of your doctor or midwife. Screening tests, scans and check-ups are scheduled by your provider.
What to do next
You may also like our BMI Calculator and Ideal Weight Calculator, or browse all free tools. Calorie and nutrition needs change during pregnancy, so ask your provider before using diet calculators.
Frequently asked questions
How is my due date calculated?
The most common method adds 280 days (40 weeks) to the first day of your last menstrual period. If your cycle is longer or shorter than 28 days, the date is adjusted. Conception, IVF transfer and early ultrasound dates can also be used.
How accurate is a due date?
A due date is an estimate. Only about 4 to 5 percent of babies are born on their exact due date, and most arrive between 37 and 42 weeks.
What if my cycle is not 28 days?
Enter your average cycle length. Ovulation usually happens about 14 days before the next period, so a longer cycle moves the due date later and a shorter cycle moves it earlier.
What is the difference between LMP dating and ultrasound dating?
LMP dating relies on your memory and a regular cycle. A first-trimester ultrasound measures the baby and is generally considered the most accurate way to date a pregnancy, so your provider may adjust your due date after a scan.
How many weeks is full term?
Early term is 37 to 38 weeks and 6 days, full term is 39 to 40 weeks and 6 days, late term is 41 to 41 weeks and 6 days, and post-term is 42 weeks or more.
When should I see a doctor?
See a doctor or midwife as soon as you think you may be pregnant. This calculator is for information only and cannot replace medical care, so follow your provider's advice and schedule.
Disclaimer: This calculator gives estimates for general information only and is not medical advice. Consult your doctor or midwife about your pregnancy.
0 Comments