Pregnancy Due Date Calculator – Free EDD from LMP

How to Use the Due Date Calculator

Enter Your LMP or Conception Date — Select the first day of your Last Menstrual Period (LMP) from the date picker, or choose to calculate from your conception date or IVF transfer date. You can also enter your average cycle length for a more personalised estimated due date.

Calculate Your Estimated Due Date — Click the Calculate button and our free EDD calculator instantly applies Naegele's Rule to determine your estimated due date. Results appear in seconds — no sign-up or personal information required — giving you your EDD and current gestational age immediately.

Review Your Pregnancy Milestones — View your full pregnancy timeline, including all three trimester start dates, key prenatal milestones, and your estimated due date. Use this information to plan doctor appointments, ultrasound scans, and important health check-ins throughout your pregnancy journey.

View your current trimester, weeks pregnant, and key dates

About Due Date Calculation

The ToolCentrix Pregnancy Due Date Calculator is a free online tool that estimates your Estimated Due Date (EDD) and tracks key milestones throughout your pregnancy. Whether you are calculating from your Last Menstrual Period (LMP), a known conception date, or an IVF transfer date, this tool delivers instant, accurate results — no sign-up, no downloads, and no cost. It is designed for expectant parents in the USA, Australia, India, and anywhere around the world.

Most due date calculators, including this one, apply Naegele's Rule — the globally accepted medical formula endorsed by the American College of Obstetricians and Gynecologists (ACOG). This method adds 280 days (40 weeks) to the first day of your last menstrual period, assuming a standard 28-day cycle. Our EDD calculator from LMP also adjusts for custom cycle lengths, giving you a more personalised estimated due date when your cycle is shorter or longer than average.

A full-term pregnancy is typically divided into three trimesters, spanning approximately 40 weeks from your LMP. The first trimester covers weeks 1 through 12, the second trimester spans weeks 13 to 26, and the third trimester runs from week 27 until delivery. Our pregnancy due date calculator displays all three trimester start dates alongside your EDD, so you can plan prenatal appointments, scans, and important health milestones with confidence.

It is important to understand that your due date is an estimate, not a guarantee. According to research published by the American Pregnancy Association, only about 4% of babies are born on their exact due date. Most healthy births occur within a window of two weeks before or after the EDD. Your healthcare provider may also adjust your due date following an early ultrasound scan, which is considered more accurate for dating a pregnancy — especially if your cycle is irregular. In Australia, Pregnancy Birth and Baby (pregnancybirthbaby.org.au) recommends a dating ultrasound between 8 and 14 weeks for the most reliable EDD.

This free pregnancy due date calculator is useful for a wide range of situations. First-time parents can use it to understand their pregnancy timeline, while those undergoing IVF or FET (Frozen Embryo Transfer) can calculate their due date based on their transfer date. Healthcare professionals, midwives, and doulas in the USA, Australia, and India also use similar gestational age calculators as a quick reference alongside formal clinical assessments.

Your privacy is completely protected when using this tool. ToolCentrix does not collect, store, or share any personal health information you enter. All calculations happen instantly in your browser. This pregnancy due date calculator is entirely free to use — unlimited times, with no registration required — making it a trusted, accessible resource for expectant parents everywhere.

Frequently Asked Questions

The Estimated Due Date (EDD) is calculated using Naegele's Rule, which adds 280 days (40 weeks) to the first day of your Last Menstrual Period (LMP). This assumes a standard 28-day cycle. If your cycle is longer or shorter, the due date is adjusted accordingly. Most doctors and midwives worldwide use this method as the baseline for pregnancy dating.

The LMP method is a reliable starting estimate, but it assumes a regular 28-day cycle and accurate recall of your last period. An early ultrasound — ideally between 8 and 14 weeks — is generally more accurate for confirming gestational age because it measures the baby directly. Your doctor may revise your EDD based on ultrasound findings, especially if there is a difference of more than 7 days.

If your menstrual cycle is shorter or longer than 28 days, a standard LMP calculation may give a slightly inaccurate due date. Our pregnancy due date calculator allows you to enter your actual average cycle length so the EDD is adjusted automatically. For cycles that vary significantly, an early ultrasound scan is the most reliable way to confirm your estimated due date.

Gestational age is counted from the first day of your Last Menstrual Period (LMP) and is the standard measure used by doctors, midwives, and pregnancy tools worldwide. Fetal age — also called embryonic age — is counted from the actual date of conception, which is typically about two weeks after your LMP. Gestational age is always approximately two weeks more than fetal age.

Yes, your due date can be revised after an ultrasound scan. If the baby's measurements differ significantly from what the LMP-based calculation predicted, your healthcare provider may update your EDD. This is most common when cycles are irregular or when the exact LMP date is uncertain. A dating ultrasound between weeks 8 and 14 provides the most accurate gestational age assessment available.

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