How is a due date calculated?

The most common method for calculating a due date is to add 280 days (40 weeks) to the first day of your last menstrual period (LMP). This is based on the assumption that conception typically occurs about 14 days into a menstrual cycle.

How accurate is a due date calculator?

Due date calculators provide an estimate, but only about 5% of babies are born on their exact due date. Most births occur within two weeks before or after the estimated due date. Ultrasound measurements in early pregnancy can provide a more accurate estimation.

Can my due date change?

Yes, your due date may change after an ultrasound, especially if there's a significant difference between the LMP-based calculation and the ultrasound measurements. Early ultrasounds (before 14 weeks) are the most accurate for dating a pregnancy.

Due Date Calculator - Estimate Your Baby's Arrival Date

📅 First Day of Your Last Menstrual Period (LMP)

🔄 Average Cycle Length (days) - Optional

Your Estimated Due Date

September 15, 2024

You are approximately 12 weeks pregnant

📋 Pregnancy Timeline

✅ First Trimester: Weeks 1-12 (Complete)
🟡 Second Trimester: Weeks 13-26 (Current)
⚪ Third Trimester: Weeks 27-40 (Upcoming)

🏥 WHO & FDA Pregnancy Recommendations

💊 Take 400-800 mcg of folic acid daily during pregnancy
🍎 Maintain a balanced diet with plenty of fruits, vegetables, and protein
🚭 Avoid alcohol, tobacco, and recreational drugs
🏥 Schedule regular prenatal check-ups with your healthcare provider
💤 Get 7-9 hours of sleep per night and rest when needed

Understanding Your Due Date Calculation

The estimated due date (EDD) is calculated by adding 280 days (40 weeks) to the first day of your last menstrual period (LMP). This method, known as Naegele's rule, assumes a 28-day menstrual cycle with ovulation occurring on day 14.

How Pregnancy Dating Works

Pregnancy is typically measured from the first day of your last menstrual period, which is about two weeks before conception actually occurs. This is because it's often difficult to determine the exact date of conception, but most people can recall when their last period started.

Factors That Can Affect Your Due Date

Cycle length: If your menstrual cycle is longer or shorter than 28 days
Ovulation timing: If you ovulate earlier or later than day 14 of your cycle
Ultrasound measurements: Early ultrasounds can provide more accurate dating

Recommended Pregnancy Products

Products to support your pregnancy journey:

💊

Prenatal Vitamins

$24.99

📚

Pregnancy Books

$19.99

🛌

Pregnancy Pillow

$49.99

❓ Frequently Asked Questions

➕ How is a due date calculated?: The most common method for calculating a due date is to add 280 days (40 weeks) to the first day of your last menstrual period (LMP). This is based on the assumption that conception typically occurs about 14 days into a menstrual cycle.
➕ How accurate is a due date calculator?: Due date calculators provide an estimate, but only about 5% of babies are born on their exact due date. Most births occur within two weeks before or after the estimated due date. Ultrasound measurements in early pregnancy can provide a more accurate estimation.
➕ Can my due date change?: Yes, your due date may change after an ultrasound, especially if there's a significant difference between the LMP-based calculation and the ultrasound measurements. Early ultrasounds (before 14 weeks) are the most accurate for dating a pregnancy.
➕ What if I don't know my last menstrual period?: If you're unsure about your LMP, an ultrasound can help estimate your due date. The earlier the ultrasound is performed, the more accurate the dating will be.
➕ What's the difference between gestational age and fetal age?: Gestational age is measured from the first day of your last menstrual period, while fetal age (also called embryonic age) is measured from the actual date of conception. Gestational age is typically about two weeks longer than fetal age.

⚠️ Medical Disclaimer: This calculator provides estimates only and is not a substitute for professional medical advice. Always consult with a qualified healthcare provider for personalized guidance regarding your pregnancy.