Due Date Pregnancy Calculator Gender Prediction

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Pregnancy Due Date & Fun Gender Predictor

Enter the first day of your last period. (Most common method)
Only enter if you know the exact date of conception. This will override LMP.
Average is 14 days. Adjust if you know your specific luteal phase length for LMP method.

Your Pregnancy Details:

Estimated Due Date:

Current Week of Pregnancy:

First Trimester Ends:

Second Trimester Ends:

Third Trimester Starts:

Fun Gender Prediction:

Disclaimer: Due dates are estimates. Gender prediction is for fun only and not scientifically accurate.

Please enter either your Last Menstrual Period (LMP) Start Date or your Conception Date.
function calculateDueDateAndGender() { var lmpDateStr = document.getElementById("lmpDate").value; var conceptionDateStr = document.getElementById("conceptionDate").value; var lutealPhaseLength = parseInt(document.getElementById("lutealPhaseLength").value); var lmpDate = new Date(lmpDateStr); var conceptionDate = new Date(conceptionDateStr); var today = new Date(); today.setHours(0, 0, 0, 0); // Normalize today's date to start of day var estimatedDueDate; var startDateForWeeks; // Date to calculate current pregnancy week from document.getElementById("result").style.display = "none"; document.getElementById("error").style.display = "none"; // Validate luteal phase length if (isNaN(lutealPhaseLength) || lutealPhaseLength 18) { lutealPhaseLength = 14; // Default to 14 if invalid } if (conceptionDateStr && !isNaN(conceptionDate.getTime())) { // Calculate based on conception date (38 weeks or 266 days) estimatedDueDate = new Date(conceptionDate.getTime()); estimatedDueDate.setDate(estimatedDueDate.getDate() + 266); startDateForWeeks = new Date(conceptionDate.getTime()); startDateForWeeks.setDate(startDateForWeeks.getDate() – 14); // For current week, assume LMP was 2 weeks before conception } else if (lmpDateStr && !isNaN(lmpDate.getTime())) { // Calculate based on LMP (40 weeks or 280 days) estimatedDueDate = new Date(lmpDate.getTime()); estimatedDueDate.setDate(estimatedDueDate.getDate() + 280); // Adjust for luteal phase length if different from 14 days if (lutealPhaseLength !== 14) { estimatedDueDate.setDate(estimatedDueDate.getDate() – 14 + lutealPhaseLength); } startDateForWeeks = lmpDate; } else { document.getElementById("error").style.display = "block"; return; } // Format due date var options = { year: 'numeric', month: 'long', day: 'numeric' }; document.getElementById("estimatedDueDate").innerText = estimatedDueDate.toLocaleDateString('en-US', options); // Calculate current week of pregnancy var diffTime = Math.abs(today.getTime() – startDateForWeeks.getTime()); var diffDays = Math.ceil(diffTime / (1000 * 60 * 60 * 24)); var currentWeeks = Math.floor(diffDays / 7); var remainingDays = diffDays % 7; document.getElementById("currentWeek").innerText = currentWeeks + " weeks and " + remainingDays + " days"; // Calculate trimester end dates var firstTrimesterEnd = new Date(startDateForWeeks.getTime()); firstTrimesterEnd.setDate(firstTrimesterEnd.getDate() + (13 * 7)); // End of week 13 var secondTrimesterEnd = new Date(startDateForWeeks.getTime()); secondTrimesterEnd.setDate(secondTrimesterEnd.getDate() + (27 * 7)); // End of week 27 var thirdTrimesterStart = new Date(startDateForWeeks.getTime()); thirdTrimesterStart.setDate(thirdTrimesterStart.getDate() + (28 * 7)); // Start of week 28 document.getElementById("firstTrimesterEnd").innerText = firstTrimesterEnd.toLocaleDateString('en-US', options); document.getElementById("secondTrimesterEnd").innerText = secondTrimesterEnd.toLocaleDateString('en-US', options); document.getElementById("thirdTrimesterStart").innerText = thirdTrimesterStart.toLocaleDateString('en-US', options); // Fun Gender Prediction (Old Wives' Tale based on Due Date Month) var dueMonth = estimatedDueDate.getMonth() + 1; // getMonth() returns 0-11 var genderPredictionText = ""; if (dueMonth % 2 === 0) { // Even month genderPredictionText = "Based on an old wives' tale, if your due date falls in an even-numbered month, it's said to be a girl!"; } else { // Odd month genderPredictionText = "Based on an old wives' tale, if your due date falls in an odd-numbered month, it's said to be a boy!"; } document.getElementById("genderPrediction").innerText = genderPredictionText; document.getElementById("result").style.display = "block"; }

Understanding Your Pregnancy Due Date and Fun Gender Prediction

Congratulations on your pregnancy! One of the first questions many expectant parents have is, "When is the baby due?" and often, "Is it a boy or a girl?" While only medical professionals can provide accurate due dates and scientific gender determination, this calculator offers an estimate for your due date and a fun, non-scientific gender prediction based on popular folklore.

How is Your Due Date Calculated?

There are a few common methods used to estimate a baby's due date, which is typically around 40 weeks (280 days) from the start of your last menstrual period (LMP) or 38 weeks (266 days) from conception.

  1. Last Menstrual Period (LMP) Method (Naegele's Rule): This is the most common method. It assumes a 28-day menstrual cycle with ovulation occurring on day 14. You simply count 280 days (40 weeks) from the first day of your last period. This calculator uses this method by default if you provide your LMP date.
  2. Conception Date Method: If you know the exact date you conceived (e.g., through IVF or precise tracking of ovulation), this can be a very accurate way to determine your due date. You add 266 days (38 weeks) to your conception date. If you enter a conception date in our calculator, it will prioritize this method.
  3. Luteal Phase Adjustment: The luteal phase is the time between ovulation and the start of your next period. While the average is 14 days, it can vary from 10 to 18 days. If you know your specific luteal phase length and are using the LMP method, adjusting for it can make your due date more accurate. For example, if your luteal phase is 12 days, your due date would be two days earlier than calculated by the standard 14-day assumption.

It's important to remember that due dates are estimates. Only about 5% of babies are born exactly on their due date. Most babies arrive between 37 and 42 weeks of gestation.

Understanding Trimesters

Pregnancy is typically divided into three trimesters, each with its own developmental milestones and maternal changes:

  • First Trimester (Weeks 1-13): This period begins with conception and is marked by rapid fetal development, including the formation of major organs. Many women experience morning sickness and fatigue during this time.
  • Second Trimester (Weeks 14-27): Often called the "golden trimester," many women feel more energetic, and morning sickness may subside. The baby's movements become noticeable, and gender can often be determined via ultrasound.
  • Third Trimester (Weeks 28-40+): The final stretch involves significant fetal growth and preparation for birth. Discomforts like back pain and frequent urination may return.

Fun Gender Prediction: Old Wives' Tales

While the only scientifically accurate ways to determine your baby's gender are through ultrasound, NIPT (Non-Invasive Prenatal Testing), or amniocentesis, many cultures have developed fun "old wives' tales" over centuries. These methods are purely for entertainment and have no scientific basis.

Our calculator uses a simple folklore method based on your estimated due date month:

  • Even-Numbered Due Date Month: Some traditions suggest that if your baby's estimated due date falls in an even-numbered month (e.g., February, April, June), you might be expecting a girl.
  • Odd-Numbered Due Date Month: Conversely, if your due date falls in an odd-numbered month (e.g., January, March, May), folklore might suggest you're having a boy.

Remember, this prediction is just for fun! The joy of pregnancy is in the journey, and the ultimate surprise of meeting your little one, regardless of gender.

Example Calculation:

Let's say your Last Menstrual Period (LMP) started on January 15, 2024, and you have a standard 14-day luteal phase.

  • LMP Date: January 15, 2024
  • Calculation: January 15, 2024 + 280 days
  • Estimated Due Date: October 22, 2024
  • Current Week (if today is June 10, 2024): Approximately 21 weeks and 0 days pregnant.
  • First Trimester Ends: April 15, 2024 (approx.)
  • Second Trimester Ends: July 22, 2024 (approx.)
  • Third Trimester Starts: July 29, 2024 (approx.)
  • Fun Gender Prediction: Since October is an even-numbered month, the old wives' tale would suggest a girl!

Use this calculator as a helpful guide and a source of fun during your pregnancy journey, but always consult with your healthcare provider for medical advice and accurate information.

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