How accurate is a pregnancy due date calculator?

A due date is an estimate. Only about 4% to 5% of babies are born on their exact due date. Most babies arrive between 37 and 42 weeks of pregnancy. The most accurate dating is established via early first-trimester ultrasound.

Why does my doctor calculate gestational age from my LMP instead of conception?

Because the exact date of conception is difficult to pinpoint for most women, whereas the start date of the last menstrual period is a clear, memorable physical event. This standard adds two weeks of 'pre-conception' time to the official gestational age.

Can my pregnancy due date change later?

Yes, if an early ultrasound scan shows measurements that differ significantly from your LMP dating (usually by more than 7 days in the first trimester), your obstetrician may adjust your official due date to match the scan.

Pregnancy Due Date & Gestational Age Calculator

Calculate your estimated due date, current trimester, and baby size milestone predictions using multiple diagnostic methods.

First Day of Last Period (LMP)

Average Cycle Length (Days)

Estimated Conception Date

Embryo Transfer Date

Embryo Age / Type

3-Day Embryo 5-Day Blastocyst

Date of Ultrasound Scan

Gestational Age at Scan

w d

Your Established Due Date

Calculate Timeline As Of (Reference Date)

Estimated Due Date (EDD)

December 25, 2026

Current Gestational Age 12 Weeks 4 Days

Current Trimester First Trimester

Days Remaining 192 Days

Estimated Conception April 3, 2026

Weekly Baby Size

Lime

Average Length 2.1 in / 5.4 cm

Average Weight 0.5 oz / 14 g

The baby can open and close their hands. Reflexes are developing, and kidneys are producing urine.

Trimester Progress

1st Trimester 2nd Trimester 3rd Trimester

31.2% Complete

Pregnancy Timeline & Clinical Milestones

About Pregnancy Due Date & Gestational Age Calculator

This online Pregnancy Due Date & Gestational Age Calculator is a simple, lightweight utility designed to help you quickly perform accurate calculations and plan your metrics. Whether you are a developer, designer, or content creator, this tool runs instantly inside your web browser without requiring any software installation, email signups, or accounts.

How to Use

Using this tool is straightforward. Simply input your data into the corresponding fields above, and the calculations or file processing will update automatically in real time. We built it with simplicity in mind so you can get your results with just a single click.

100% Secure & Private

We respect your privacy. Almost all calculations and operations on Apex Tools Hub are performed entirely on the client side using JavaScript. This means your text, images, files, or financial details are never sent to our servers or stored anywhere. Everything stays safe on your own device.

Frequently Asked Questions

Are my files or inputs stored on the server?

No. We do not upload or store any data from our tools. All processing is executed locally in your browser, guaranteeing complete data privacy.

Is this tool free?

Yes. All utilities on Apex Tools Hub are completely free to use. There are no daily limits, hidden costs, or paid features.

Can I use this tool offline?

Yes. Once you load this page in your browser, the tool operates using local JavaScript code, allowing you to use it even without an active internet connection.

Conclusion: Empowering Your Pregnancy Journey

Understanding your pregnancy due date and gestational age provides a sense of clarity and empowerment during a time of immense physical and emotional change. Whether you are using your LMP, IVF transfer dates, or early scans, tracking your timeline helps you collaborate effectively with your healthcare providers. Remember that your body is working on a wise, natural schedule. Use this tool to plan, prepare, and stay informed, but always consult with your OB/GYN or midwife to establish your final, official clinical care plan.