When Baby Is Due Calculator

Pregnancy due dates are typically calculated based on the first day of your last menstrual period (LMP). This calculator estimates your due date by adding 40 weeks (280 days) to your LMP date. Keep in mind that due dates are estimates and actual delivery dates can vary.

How to Use This Calculator

To calculate your estimated due date:

Enter the date of your first day of your last menstrual period (LMP).
Click the "Calculate" button.
Review the estimated due date and related information.

The calculator will show you the estimated due date, the date of conception, and the date of the first trimester ultrasound.

How the Due Date Calculation Works

The standard due date calculation adds 40 weeks (280 days) to the first day of your last menstrual period (LMP). This is based on the average length of a full-term pregnancy.

Due Date = LMP Date + 280 days

For example, if your LMP was on January 1, 2023, your estimated due date would be October 31, 2023.

Note that this is an estimate. Actual delivery dates can vary by several days or weeks.

Example Calculation

Let's say your last menstrual period started on May 15, 2023. Here's how the calculation works:

LMP Date: May 15, 2023

Estimated Due Date: May 15, 2023 + 280 days = February 12, 2024

Date of Conception: May 15, 2023 - 14 days = April 30, 2023

First Trimester Ultrasound: May 15, 2023 + 12 weeks = August 12, 2023

This example shows the estimated due date, the approximate date of conception, and when you would typically have your first trimester ultrasound.

Frequently Asked Questions

How accurate is the due date calculator?: The due date calculator provides an estimate based on standard pregnancy length. Actual delivery dates can vary by several days or weeks.
What if I don't know my exact LMP date?: If you're unsure of your exact LMP date, you can estimate based on the first day of your last menstrual period. The calculator will still provide a useful estimate.
When should I have my first trimester ultrasound?: Most healthcare providers recommend having your first trimester ultrasound between 11 and 14 weeks of pregnancy, which is typically around 3-4 months after your LMP date.
What if my pregnancy is high-risk?: If you have a high-risk pregnancy, your healthcare provider may recommend more frequent monitoring and may adjust the due date calculation based on your specific situation.
Can I use this calculator for multiple pregnancies?: Yes, you can use this calculator for each pregnancy by entering the appropriate LMP date for each pregnancy.