Baby Due Date Calculator – Estimate Your Pregnancy Timeline

The Baby Due Date Calculator gives expectant parents one of the first and most eagerly anticipated numbers in any pregnancy — the estimated due date. From the moment a pregnancy is confirmed, that date becomes a central reference point for everything that follows: prenatal appointments, maternity leave planning, nursery preparation, and the gradual countdown that marks every week of the journey. This calculator works from either your last menstrual period or your known conception date, whichever you have available, and returns your estimated due date alongside your current gestational age and the key trimester milestone dates — all laid out in a table and a visual pregnancy timeline so you have the full picture from the very first calculation.

How the Calculation Works: From Last Menstrual Period (LMP): EDD = LMP + 280 days, adjusted for cycle length variations away from 28 days From Conception Date: EDD = Conception Date + 266 days Both methods use the standard clinical gestation periods that obstetricians and midwives apply in practice.

How to Use the Baby Due Date Calculator

The calculation requires just a date and a choice of method:

Select Your Calculation Method by choosing either Last Menstrual Period (LMP) or Conception Date from the dropdown. Most people use the LMP method because the first day of the last period is easier to pinpoint than the exact date of conception. If you do know your conception date — from fertility tracking, IVF, or confirmed ovulation — the conception date method gives a more direct calculation.

Enter Your Date using the date picker — either the first day of your last menstrual period or your confirmed conception date, depending on the method you selected. Getting this date right is the single most important factor in the accuracy of your estimated due date.

Enter Your Cycle Length (LMP Method Only) in days if you are using the LMP method and your cycle is not the standard 28 days. Entering your actual average cycle length allows the calculator to adjust the ovulation timing assumption accordingly, producing a more accurate EDD for cycles that are notably shorter or longer than average.

Click Calculate and your estimated due date appears immediately alongside your current gestational age in weeks and days, the dates when each trimester ends, and a pregnancy timeline chart that maps the full 40-week journey from your LMP or conception date through to your due date.

Why Use the Baby Due Date Calculator Online?

Two Calculation Methods for Different Situations: Not everyone has the same starting information. The LMP method is the standard clinical approach and works well for most people. The conception date method is there for those who have more precise knowledge of when conception occurred — through fertility treatment, ovulation tracking, or confirmed test results — and want a calculation that starts from that known point directly.

Cycle Length Adjustment for More Accurate Results: The standard 280-day pregnancy calculation assumes a 28-day cycle with ovulation on day 14. If your cycle is consistently shorter or longer than that, applying your actual average cycle length shifts the ovulation assumption and produces an EDD that is better calibrated to your body rather than a population average.

Trimester Milestone Dates Included Automatically: Knowing your due date is important, but knowing when you move from the first trimester into the second, and from the second into the third, helps you understand where you are in the pregnancy and what to expect at each stage. These milestone dates appear automatically in the results table without any extra input needed.

Visual Pregnancy Timeline for a Clear Overview: The timeline chart maps out your entire pregnancy from start to due date in a single visual, showing how far along you currently are and how each trimester sits within the full 40-week arc. This kind of visual context is something a table of dates alone does not always convey as clearly.

Gestational Age Displayed to the Week and Day: Your current gestational age is shown in weeks and days at the time of calculation, which is exactly the format used in clinical settings and prenatal care discussions. This makes the result immediately useful for conversations with healthcare providers.

Free, Private, and Instantly Available: No account needed, no personal data stored, and no cost at all. Enter your date and receive your estimated due date with full pregnancy milestone details in seconds.