Due Date Calculator

- May 09, 2025
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Calculate your estimated due date based on your last menstrual period, conception date, or ultrasound information. This calculator provides an approximate due date and important pregnancy milestones.

Calculation Method

Advanced Options

About Due Date Calculations

The average pregnancy lasts about 40 weeks (280 days) from the first day of the last menstrual period (LMP). Due dates are just estimates – only about 5% of babies are born on their exact due date.

Calculation Methods
  • Last Menstrual Period (LMP): The most common method. Adds 280 days (40 weeks) to the first day of your last period.
  • Conception Date: Adds 266 days (38 weeks) to the date of conception, which is typically about 14 days after the start of the last period.
  • Ultrasound Dating: Uses measurements taken during an ultrasound to determine gestational age, then calculates the due date.
Trimesters

Pregnancy is divided into three trimesters, each lasting about 13-14 weeks:

  • First Trimester: Weeks 1-13 (development of major organs and systems)
  • Second Trimester: Weeks 14-26 (rapid growth and movement)
  • Third Trimester: Weeks 27-40 (final development and preparation for birth)
Terms to Know
  • Gestational Age: Time measured from the first day of the last menstrual period (LMP)
  • Embryonic Age/Fetal Age: Time measured from conception (typically 2 weeks less than gestational age)
  • Full-term: Between 39 weeks, 0 days and 40 weeks, 6 days
  • Early-term: Between 37 weeks, 0 days and 38 weeks, 6 days
  • Late-term: Between 41 weeks, 0 days and 41 weeks, 6 days
  • Post-term: 42 weeks, 0 days and beyond

Understanding the Due Date Calculator

The Due Date Calculator is a helpful tool designed for expecting parents. It allows users to estimate their baby's due date using various methods. By entering specific data, such as the first day of your last menstrual period (LMP), the conception date, or information from an ultrasound, you can find out when your baby is likely to arrive. This tool not only provides an estimated due date but also highlights important Pregnancy milestones.

How to Calculate Your Due Date

Using the Due Date Calculator is straightforward. You can choose from three different calculation methods:

  • Last Menstrual Period (LMP): Ideal for those tracking their menstrual cycle.
  • Conception Date: Useful for those who know when they conceived.
  • Ultrasound Data: Best for those who have had an ultrasound and want to use that information.

Inputting Your Information

Once you’ve chosen your calculation method, you’ll need to input the relevant details. For LMP, you’ll enter the first day of your last period along with your average cycle length. If you select the conception date, just provide that specific date. For ultrasound dating, you’ll enter the ultrasound date and the gestational age noted at the time. Each method is designed to give you the most accurate due date possible based on the data you provide.

Receiving Your Results

After entering your information, the calculator will display several key results. These include your estimated due date, current gestational age, and the end dates for each trimester. This information helps you understand where you are in your pregnancy and what to expect in the coming weeks. You’ll also get a breakdown of important milestones to look forward to during your pregnancy.

Understanding Pregnancy Milestones

The calculator also offers insights into critical pregnancy milestones. Knowing these milestones can be beneficial for planning and preparation. Here are some key milestones you might encounter:

  • First Trimester Ends: This marks the completion of the initial 13 weeks.
  • Second Trimester Ends: You’ll reach the halfway point of your pregnancy at this stage.
  • Full-term: Understanding when you’re considered full-term is vital for planning your baby's arrival.

Advanced Features of the Calculator

For those looking for more detailed insights, the Due Date Calculator includes advanced options. You can choose to view a pregnancy calendar, which visually represents your pregnancy journey. Additionally, there’s an option to show lunar months, providing an alternative perspective on your pregnancy timeline. These features enhance the overall experience, making it easier to track your pregnancy and prepare for your baby.

Why Due Dates Matter

Knowing your estimated due date is significant for several reasons. It helps you plan for prenatal visits, baby showers, and Other preparations for the arrival of your child. While due dates are estimates and only about 5% of babies are born on their exact due date, having a target date can provide a sense of readiness and excitement for the journey ahead.

Getting the Most from the Due Date Calculator

To make the most of the Due Date Calculator, ensure you input accurate information. Regularly check in with your healthcare provider throughout your pregnancy to discuss your due date and any adjustments that may be necessary based on ultrasounds or other medical advice. This calculator is a great starting point, but your healthcare provider will provide additional insights to guide you on this important journey.