Due Date Calculator by First Positive Test

How to Use This Calculator

To calculate your estimated due date using the first positive test:

1. Enter the date of your first positive pregnancy test result.
2. Click the "Calculate" button.
3. Review your estimated due date and pregnancy timeline.

The calculator will show you your estimated due date, the number of weeks since your first positive test, and a pregnancy timeline chart.

How the Due Date Calculation Works

When you have your first positive pregnancy test, the average gestation period is about 40 weeks from conception. The due date is typically calculated as 40 weeks after the first day of your last menstrual period (LMP).

However, when you know the date of your first positive test, you can estimate your due date by adding 280 days (40 weeks) to that date. This method provides a more accurate estimate of your due date compared to using the LMP method alone.

This calculation assumes a normal pregnancy duration of 40 weeks. Keep in mind that individual pregnancies may vary, and medical professionals will provide more precise due dates during prenatal visits.

Example Calculation

Let's say you had your first positive pregnancy test on May 15, 2023. Using the calculator:

1. Enter May 15, 2023 as the first positive test date.
2. Click "Calculate".

The calculator will show that your estimated due date is February 12, 2024 (280 days after May 15, 2023).

This means you would be in your 40th week of pregnancy on February 12, 2024.