Pregnancy Due Date Calculator
Find your estimated due date, how far along you are, and when each trimester starts, using the first day of your last period or the date of conception.
Free · No sign-up · Files stay on your device
How to use Pregnancy Due Date Calculator
- 1Choose "Last period" or "Conception date".
- 2Enter the date (and your usual cycle length if you know it).
- 3Read your due date, current week and milestones.
Features
- From last period or conception date
- Adjusts for cycle length
- Current week and day of pregnancy
- Trimester dates and milestones
- Private: nothing is saved
How the due date is calculated
Pregnancy is counted from the first day of your last menstrual period. The due date is 280 days (40 weeks) after it, adjusted if your cycle is longer or shorter than 28 days. From a known conception date, it is 266 days later.
Only an estimate
Only about 1 in 20 babies arrive on their due date; most are born within two weeks either side. Your doctor or midwife may update the date after an early ultrasound scan, which is the most accurate method.
Frequently asked questions
What if my cycle is irregular?
The estimate is less reliable. An early ultrasound gives a more accurate due date.
When does each trimester start?
The second trimester starts at week 13 and the third at week 28.
Can I use this for IVF?
Use the conception date option with your embryo transfer date adjusted by your clinic's guidance, or ask your clinic for the exact due date.