Calculate your due date, pregnancy week, and trimester based on your last menstrual period (LMP) or conception date. Track your pregnancy progress with our free pregnancy calculator.
Enter the first day of your last menstrual period
This tool is for informational and educational purposes only. It is not a substitute for professional medical, nutritional, or health advice. For diagnosis, treatment, or personalized guidance, please consult a qualified healthcare provider.
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Calculating your due date and tracking your pregnancy progress is an exciting and important part of pregnancy. Our free pregnancy calculator helps you determine your estimated due date, current pregnancy week, and trimester based on your last menstrual period (LMP) or conception date. Whether you're newly pregnant, planning a pregnancy, or tracking your pregnancy journey, our pregnancy calculator provides accurate estimates to help you understand your pregnancy timeline and prepare for your baby's arrival.
Pregnancy calculations are based on the standard 40-week (280-day) pregnancy duration, calculated from the first day of your last menstrual period (LMP). This method is used by healthcare providers worldwide because it's easier to determine than the actual conception date, which can vary. Our pregnancy calculator uses this standard method to provide accurate due date estimates.
Pregnancy is typically divided into three trimesters, each lasting approximately 13-14 weeks. The first trimester (weeks 1-13) includes early development and is when most women discover they're pregnant. The second trimester (weeks 14-27) is often called the "honeymoon period" with reduced symptoms. The third trimester (weeks 28-40+) is the final stretch leading to delivery.
The standard method for calculating due dates is called Naegele's Rule, which adds 280 days (40 weeks) to the first day of your last menstrual period. This method assumes a 28-day menstrual cycle with ovulation on day 14, though actual cycles can vary. Our pregnancy calculator uses this standard method, which is the same approach used by healthcare providers.
While the calculation is straightforward, actual delivery dates can vary significantly. Only about 5% of babies are born exactly on their due date. Most births occur within 2 weeks before or after the due date, which is considered normal. Our pregnancy calculator provides an estimated due date, but your healthcare provider will refine this estimate using ultrasound measurements as your pregnancy progresses.
Pregnancy is typically calculated from the LMP rather than the conception date for several reasons:
If you know your conception date, you can calculate your due date by adding 266 days (38 weeks) instead of 280 days. However, LMP-based calculation is the standard and most commonly used method. Our pregnancy calculator primarily uses LMP, but can work with conception dates if needed.
Understanding pregnancy weeks and trimesters helps you track your pregnancy progress:
The first trimester is crucial for fetal development. During this time, the baby's major organs and body systems begin to form. Common symptoms include morning sickness, fatigue, and breast tenderness. Our pregnancy calculator shows which week of the first trimester you're in, helping you understand what to expect during early pregnancy.
The second trimester is often the most comfortable period of pregnancy. Morning sickness typically subsides, energy levels increase, and you may feel the baby move for the first time. Our pregnancy calculator tracks your progress through the second trimester, showing how many weeks remain until the third trimester.
The third trimester is the final stretch of pregnancy. The baby grows rapidly, and you may experience increased discomfort, frequent urination, and preparation for labor. Our pregnancy calculator shows how many weeks remain until your due date, helping you prepare for delivery.
Our pregnancy calculator is designed to be simple and accurate. Here's how to use it:
Enter the first day of your last menstrual period. This is the date your period started, not when it ended. If you're unsure of the exact date, use your best estimate. The more accurate your LMP date, the more accurate your due date estimate will be.
The calculator instantly displays:
Remember that due dates are estimates, not guarantees. Most babies are born within 2 weeks before or after the due date. Your healthcare provider will use ultrasound measurements to refine the due date as your pregnancy progresses, especially during the first trimester when measurements are most accurate.
Several factors can affect the accuracy of due date calculations:
Our pregnancy calculator provides a good starting estimate, but your healthcare provider will use additional information to refine the due date throughout your pregnancy.
Understanding pregnancy milestones helps you track your baby's development:
During early pregnancy, the baby's major organs begin to form. The heart starts beating, and basic body structures develop. Our pregnancy calculator shows you're in the first trimester during this critical development period.
The baby grows rapidly, and external features become more defined. You may have your first ultrasound during this period, which can help refine your due date. Our pregnancy calculator continues tracking your progress through these important weeks.
The baby's movements become more coordinated, and you may feel kicks and movements. The baby can hear sounds and respond to stimuli. Our pregnancy calculator shows your progress through the second trimester, often the most comfortable period of pregnancy.
The baby gains weight rapidly and prepares for birth. You may experience increased discomfort and preparation for labor. Our pregnancy calculator shows how many weeks remain until your due date, helping you prepare for delivery.
Pregnancy calculators are useful for:
Our pregnancy calculator provides all this information instantly, making it easy to plan and prepare for your pregnancy journey.
While our pregnancy calculator provides useful estimates, remember:
Our pregnancy calculator is a helpful tool for understanding your pregnancy timeline, but it should be used alongside regular healthcare provider consultations.
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Calculating your due date and tracking your pregnancy progress is an important part of the pregnancy journey. Our free pregnancy calculator helps you determine your estimated due date, current pregnancy week, and trimester based on your last menstrual period. While due dates are estimates and actual delivery dates can vary, our pregnancy calculator provides a helpful starting point for understanding your pregnancy timeline. Use it to plan maternity leave, prepare for your baby's arrival, track developmental milestones, and understand what to expect during each stage of pregnancy. Remember to consult with healthcare providers for medical advice and to attend regular prenatal care appointments for a healthy pregnancy journey.
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To calculate your due date, enter your last menstrual period (LMP) date. The standard calculation adds 280 days (40 weeks) to your LMP date. Our pregnancy calculator uses this method, which is the most common approach used by healthcare providers. You can also calculate based on conception date by adding 266 days (38 weeks).
LMP (Last Menstrual Period) is the first day of your last period before pregnancy, while conception date is when fertilization actually occurred. Pregnancy is typically calculated from LMP because it's easier to determine and adds about 2 weeks before actual conception. Our pregnancy calculator can work with either date, but LMP is the standard method used by doctors.
The pregnancy calculator provides an estimated due date based on standard calculations. However, actual delivery dates can vary. Only about 5% of babies are born exactly on their due date, with most births occurring within 2 weeks before or after. Your healthcare provider will use ultrasound measurements to refine the due date as your pregnancy progresses.
Pregnancy is divided into three trimesters, each lasting about 13-14 weeks. The first trimester is weeks 1-13, the second trimester is weeks 14-27, and the third trimester is weeks 28-40+. Our pregnancy calculator shows which trimester you're in based on your current pregnancy week, helping you understand your pregnancy timeline and what to expect during each stage.