Pregnancy Calculator
Pregnancy calculator estimates your due date and tracks pregnancy progress based on your last menstrual period or conception date. See which trimester you're in, how many weeks along you are, and important pregnancy milestones. This calculator uses the standard 40-week pregnancy timeline used by healthcare providers.
Select the first day of your last menstrual period
Estimated date of conception or ovulation
Estimated Due Date
January 1, 2026
You are 12 weeks pregnant
Pregnancy Progress
120 days remaining
First Trimester
Weeks 1-13
Second Trimester
Weeks 14-27
Third Trimester
Weeks 28-40
Conception Date
Feb 1, 2025
Days Pregnant
84 days
Important Information
This calculator provides an estimate based on standard 40-week pregnancy calculations. Every pregnancy is unique. Only an ultrasound can determine your due date with greater accuracy. Always consult with your healthcare provider for personalized prenatal care and important health decisions.
Frequently Asked Questions
- How is my due date calculated?
- Due dates are calculated by adding 280 days (40 weeks) to the first day of your last menstrual period. This is called Naegele's rule and is the standard method used by healthcare providers worldwide.
- Why is pregnancy 40 weeks if it's only 9 months?
- Pregnancy is typically 40 weeks from your last menstrual period, which equals about 9 months and 1 week. This is because pregnancy counting starts from your LMP, about 2 weeks before conception actually occurs.
- How accurate is this calculator?
- This calculator provides an estimate. Only about 5% of babies are born exactly on their due date. Most babies are born between 38-42 weeks. An ultrasound, especially in the first trimester, provides the most accurate due date.
- What's the difference between LMP and conception date?
- LMP (Last Menstrual Period) is the first day of your last period. Conception typically occurs about 2 weeks after LMP, during ovulation. If you know your conception date, you can calculate more precisely.
- When do trimesters start and end?
- First trimester: Weeks 1-13, Second trimester: Weeks 14-27, Third trimester: Weeks 28-40. Each trimester is approximately 13 weeks long and marks different developmental stages.
- Can my due date change?
- Yes. Your healthcare provider may adjust your due date after an early ultrasound, which can measure fetal development more accurately than date-based calculations.