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Why Every Parenting Blog Needs a Due Date Calculator
If you run a pregnancy or parenting blog, you already know that your readers are hungry for practical, trustworthy tools. One of the most searched topics in the pregnancy niche is "when is my baby due?" — and that means a pregnancy due date calculator embedded directly on your blog is one of the highest-value features you can offer. Instead of sending visitors away to generic third-party sites, you can keep them engaged on your own pages, boost your dwell time, and grow your authority as a go-to resource for expecting parents.
In this tutorial, you will learn exactly how to build a due date calculator using a simple Google Sheets formula, and then embed it beautifully on your parenting blog using GSheetPress — no coding required. By the end, you will have a fully functional, mobile-friendly calculator that feels native to your site and genuinely helps your audience.
Understanding the LMP-Based Due Date Formula
The most widely used method for calculating a pregnancy due date is called Naegele's Rule, which is based on the date of the Last Menstrual Period (LMP). According to this method, a full-term pregnancy lasts approximately 280 days — or 40 weeks — from the first day of the last menstrual period.
The formula is straightforward:
- Due Date = LMP Date + 280 days
This is the same calculation used by most healthcare providers for an initial estimated due date (EDD). You can read more about how clinicians use this method on the American College of Obstetricians and Gynecologists (ACOG) website, which offers detailed clinical guidance on due date estimation.
In Google Sheets, this formula is remarkably simple to implement. If you place the user's LMP date in cell B2, the formula for the due date would be:
=B2+280
You can also calculate the current gestational age in weeks using:
=INT((TODAY()-B2)/7) &