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Pregnancy Due Date Calculator

Calculate your estimated due date and track important pregnancy milestones.

Calculate Your Due Date

Understanding Due Dates

Your due date, also called the estimated date of delivery (EDD), is calculated as:

  • For LMP method: LMP + 280 days (40 weeks)
  • For conception date: Conception + 266 days (38 weeks)

Keep in mind:

  • Only about 5% of babies are born exactly on their due date
  • Most babies are born within 2 weeks before or after
  • The due date is just an estimate - every pregnancy is unique
  • For irregular cycles, an early ultrasound provides the most accurate dating

For medical advice about your pregnancy, always consult with your healthcare provider.

Your Estimated Due Date

April 15, 2025

Based on your last menstrual period, your baby is expected to arrive around this date. Remember that only about 5% of babies are born exactly on their due date.

Current Pregnancy Status

14 weeks, 3 days
Second Trimester

You are currently in your second trimester. Your baby is about the size of a lemon and developing rapidly. You might start feeling movement soon!

Pregnancy Timeline

First Trimester
Second Trimester
Third Trimester

First Trimester: Weeks 1-13

The first trimester is crucial for your baby's development. All major organs and structures begin to form during this period.

Weeks 1-4

Fertilization occurs and the embryo implants in the uterus. The neural tube (future brain and spinal cord) begins to form.

Weeks 5-8

Baby's heart begins to beat. Arms, legs, eyes, and ears start developing. Baby is now called a fetus.

Weeks 9-13

All essential organs have formed. Baby begins to move, though you won't feel it yet. External genitalia start to develop.

Second Trimester: Weeks 14-27

Many women find the second trimester to be easier than the first. Morning sickness often subsides, and you'll start to feel your baby move.

Weeks 14-18

Baby's facial features develop. You may begin feeling movements ("quickening"). Skin is covered with fine hair (lanugo).

Weeks 19-22

Baby's movements become stronger. A typical anatomy scan ultrasound is performed around 20 weeks. Baby develops a sleep-wake cycle.

Weeks 23-27

Baby responds to sounds and light. Fingerprints and footprints form. Baby gains significant weight and has a chance of survival if born prematurely.

Third Trimester: Weeks 28-40

Your baby continues to grow and prepare for birth. You might experience more discomfort as your body accommodates your growing baby.

Weeks 28-31

Baby's brain and lungs continue developing rapidly. Eyes open and close. Baby can regulate body temperature.

Weeks 32-35

Baby gains weight and stores fat. Most babies turn head-down in preparation for birth. Lungs are nearly mature.

Weeks 36-40

Baby is considered full-term after 37 weeks. Final weight gain occurs. Baby drops lower into the pelvis as birth approaches.

Due Date Accuracy
Prenatal Care
Fetal Development
Pregnancy Health

Understanding Due Date Accuracy

Your estimated due date (EDD) is just that - an estimate. Here's what you should know about due date accuracy:

  • Only about 5% of women deliver exactly on their due date
  • About 70% of women give birth within 10 days of their due date
  • A pregnancy is considered "term" from 37 to 42 weeks
  • First-time mothers often deliver later than their due date
  • Women who've given birth before tend to deliver closer to their due date

The most accurate methods for determining due dates, in order of reliability, are:

  1. Early ultrasound (before 20 weeks)
  2. Known date of conception (IVF or precisely tracked ovulation)
  3. Last menstrual period (LMP) with regular cycles

If your cycles are irregular or you're unsure of your LMP, an early ultrasound provides the most accurate due date.

Essential Prenatal Care

Regular prenatal care is crucial for a healthy pregnancy. Here's a general schedule of recommended prenatal visits:

  • Weeks 4-28: Every 4 weeks
  • Weeks 28-36: Every 2 weeks
  • Weeks 36-birth: Weekly

Important prenatal screenings and tests typically include:

  • First trimester: Initial blood work, dating ultrasound, genetic screening options
  • Second trimester: Anatomy scan ultrasound (around 20 weeks), glucose screening test
  • Third trimester: Group B strep test, fetal position check

Additional prenatal care recommendations:

  • Take a prenatal vitamin with folic acid
  • Stay hydrated and maintain a balanced diet
  • Avoid alcohol, tobacco, and unprescribed medications
  • Discuss any concerns with your healthcare provider

Fetal Growth & Development Milestones

Your baby develops at an amazing pace throughout pregnancy. Here are some key development milestones:

First Trimester

  • Week 5: Heart begins to form and beat
  • Week 6: Neural tube closes, brain and spinal cord developing
  • Week 8: All major organs beginning to form
  • Week 10: Fingers and toes are formed
  • Week 12: External genitalia begin to show gender differentiation

Second Trimester

  • Week 16: Baby can make facial expressions
  • Week 18: Baby begins to hear sounds
  • Week 20: Lanugo (fine hair) covers the body
  • Week 23: Fingerprints and footprints form
  • Week 24: Real hair begins to grow

Third Trimester

  • Week 30: Brain undergoes significant development
  • Week 32: Baby practices breathing movements
  • Week 35: Most babies turn head-down
  • Week 37: Baby is considered full-term
  • Week 40: Average length of pregnancy

Pregnancy Health & Wellness Tips

Taking care of yourself is essential during pregnancy. Here are some health and wellness recommendations:

Nutrition

  • Increase caloric intake by about 300-500 calories daily (2nd and 3rd trimesters)
  • Focus on nutrient-dense foods like fruits, vegetables, whole grains, and lean proteins
  • Stay hydrated with 8-10 glasses of water daily
  • Consider foods rich in folate, iron, calcium, and omega-3 fatty acids
  • Avoid unpasteurized dairy, raw seafood, undercooked meat, and high-mercury fish

Physical Activity

  • Aim for at least 30 minutes of moderate activity most days
  • Walking, swimming, and prenatal yoga are excellent options
  • Avoid activities with high fall risk or abdominal impact
  • Listen to your body and don't overexert yourself

Mental Wellbeing

  • Practice stress reduction techniques like meditation or deep breathing
  • Connect with other expectant parents through classes or support groups
  • Communicate openly with your partner about changing needs and emotions
  • Discuss any persistent anxiety or depression with your healthcare provider

Rest & Comfort

  • Sleep on your side (particularly the left) in later pregnancy
  • Use pregnancy pillows for support
  • Rest when tired and take short breaks throughout the day
  • Wear supportive, comfortable shoes and clothing
Picture of Dr. Evelyn Carter

Dr. Evelyn Carter

Author | Chief Calculations Architect & Multi-Disciplinary Analyst

Table of Contents

Pregnancy Due Date Calculator: Accurately Predict Your Baby’s Arrival

Wondering when you’ll meet your little one? Our Pregnancy Due Date Calculator provides a reliable estimate of your baby’s arrival date based on your last menstrual period or conception date, helping you track important milestones throughout your pregnancy journey.

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How Our Pregnancy Due Date Calculator Works

This comprehensive calculator uses medical standards to determine your estimated due date (EDD):

Calculation Methods

  • Last Menstrual Period Method – Adding 280 days (40 weeks) to the first day of your last period
  • Conception Date Method – Adding 266 days (38 weeks) to your known conception date
  • Cycle Length Adjustment – Customizing calculations based on your typical menstrual cycle

The calculator also provides a detailed pregnancy timeline, trimester breakdown, and fetal development information to guide you through each stage of your pregnancy.

Why Due Date Accuracy Matters

Your estimated due date serves as an essential reference point for:

  • Monitoring fetal growth and development at appropriate intervals
  • Scheduling prenatal tests and screenings at optimal times
  • Planning maternity leave and preparation for baby’s arrival
  • Determining gestational age if complications arise
  • Making informed decisions about interventions if pregnancy extends beyond 40 weeks

While only about 5% of babies arrive exactly on their due date, understanding this timeline helps you and your healthcare provider ensure the best possible care throughout your pregnancy.

Understanding Your Pregnancy Timeline

Once you calculate your due date, you’ll gain insights into:

First Trimester (Weeks 1-13)

The foundation of your baby’s development occurs during these initial weeks. All major organs and body systems begin to form, and your body undergoes significant hormonal changes.

Key Milestones:

  • Week 5-6: Baby’s heart begins beating
  • Week 8: All major organs start forming
  • Week 12: External genitalia start developing

Common Experiences:

  • Morning sickness
  • Fatigue
  • Breast tenderness
  • Frequent urination

Second Trimester (Weeks 14-27)

Often called the “golden period” of pregnancy, many women find the second trimester more comfortable as morning sickness typically subsides and energy levels increase.

Key Milestones:

  • Week 16-20: First noticeable baby movements
  • Week 18-22: Anatomy scan ultrasound typically performed
  • Week 23: Baby begins to hear sounds

Common Experiences:

  • Increased energy
  • Growing baby bump
  • Less frequent urination
  • Potential nasal congestion and gum sensitivity

Third Trimester (Weeks 28-40)

The final stretch before meeting your baby. Your baby gains significant weight while completing development of vital organs and systems.

Key Milestones:

  • Week 32: Baby practices breathing movements
  • Week 35-36: Baby typically moves into head-down position
  • Week 37: Baby is considered full-term

Common Experiences:

  • Shortness of breath
  • Trouble sleeping
  • Braxton Hicks contractions
  • Lower back pain
  • Increased fatigue

Due Date Accuracy Factors

Several factors influence the precision of your estimated due date:

Menstrual Cycle Regularity

Women with regular cycles tend to have more accurate due dates than those with irregular cycles.

Early Ultrasound Dating

An ultrasound performed before 20 weeks of pregnancy can provide the most accurate due date estimation, especially if you’re unsure about your last period.

Previous Pregnancy Patterns

If you’ve had children before, your pregnancy length might follow similar patterns.

Multiple Pregnancies

Twins, triplets, and other multiples typically arrive earlier than singleton pregnancies.

Maternal Age

Advanced maternal age may slightly increase the likelihood of delivering before your due date.

Our calculator accounts for cycle length variations, but for the most accurate dating, always consult with your healthcare provider, especially if you have irregular cycles or are unsure about your dates.

Prenatal Care Based on Your Due Date

Once you know your due date, you can plan your prenatal care appointments, which typically follow this schedule:

Weeks 4-28

Monthly visits

Weeks 28-36

Visits every two weeks

Weeks 36-birth

Weekly visits

Important screenings are timed based on your due date:

  • Weeks 11-14: First-trimester screening
  • Weeks 15-20: Quad screen blood test
  • Weeks 18-22: Anatomy scan ultrasound
  • Weeks 24-28: Glucose screening test
  • Weeks 35-37: Group B strep test

Preparing for Baby’s Arrival

Knowing your due date helps you create a timeline for essential preparations:

3-4 Months Before Due Date

  • Begin setting up the nursery
  • Start baby registry
  • Research childcare options if needed
  • Consider childbirth education classes

2 Months Before Due Date

  • Prepare and freeze meals
  • Install car seat
  • Pack hospital bag
  • Finalize birth plan

1 Month Before Due Date

  • Complete baby-proofing essentials
  • Arrange for help after baby arrives
  • Practice routes to the hospital/birth center
  • Finalize maternity/paternity leave details

When to Contact Your Healthcare Provider

While our calculator provides an estimate, always consult with your healthcare provider if you experience:

  • Irregular periods or uncertain last menstrual period date
  • Unusual spotting or bleeding during pregnancy
  • Previous premature births
  • Medical conditions that might affect pregnancy duration
  • Signs of preterm labor

Frequently Asked Questions About Due Dates

How accurate is the due date calculator?

Due date calculations are estimates. Only about 5% of women deliver exactly on their due date, but about 70% deliver within 10 days of it. Factors like irregular cycles and first-time pregnancies can affect accuracy.

What if my cycles are irregular?

If your cycles are irregular, the calculation based on last menstrual period may be less accurate. In this case, an early ultrasound (before 20 weeks) provides the most reliable due date estimation.

Can my due date change?

Yes, your healthcare provider might adjust your due date based on ultrasound measurements, especially during early pregnancy when dating is most accurate.

What’s the difference between gestational age and fetal age?

Gestational age is calculated from the first day of your last menstrual period (typically 2 weeks before conception) and is what healthcare providers use. Fetal age refers to the actual time since conception.

What if I go past my due date?

Going 1-2 weeks past your due date is common, especially for first-time mothers. Your healthcare provider will monitor you and baby closely and might recommend induction if you go significantly past your due date.

Does cycle length really matter for calculating due date?

Yes, the standard calculation assumes a 28-day cycle with ovulation on day 14. If your cycle is consistently longer or shorter, our calculator adjusts for more accurate results.

Related Health Calculators

Continue your pregnancy and health planning with these complementary calculators:

Medical Basis for Due Date Calculation

The methods used in this calculator are based on established medical research and practices:

  • The 280-day (40-week) calculation from LMP was established by German obstetrician Franz Naegele in the early 1800s and remains the standard method used today.
  • Research published in Human Reproduction confirms that cycle length variations can significantly impact conception timing and due date accuracy.
  • A study in the American Journal of Obstetrics and Gynecology found that first-trimester ultrasound provides the most accurate pregnancy dating.
  • The Journal of Midwifery & Women’s Health reports that only about 5% of women deliver on their calculated due date, with most delivering within 10 days before or after.

These evidence-based approaches ensure our calculator provides reliable estimates while acknowledging the natural variability of pregnancy.

A Note on Pregnancy Health

While tracking your due date is exciting, remember that a healthy pregnancy involves:

  • Regular prenatal care visits
  • Balanced nutrition
  • Appropriate physical activity
  • Adequate rest
  • Avoiding alcohol, tobacco, and unprescribed medications
  • Managing stress

Health Disclaimer

The Pregnancy Due Date Calculator and accompanying information are provided for educational purposes only. This tool is not intended to replace professional medical advice, diagnosis, or treatment.

While the calculator uses standard medical formulas for estimating due dates, every pregnancy is unique and may not follow average timelines. Individual assessment by qualified healthcare providers is essential for proper prenatal care.

Always consult with qualified healthcare professionals before making any decisions regarding your pregnancy.

Last Updated: March 16, 2025 | Next Review: March 16, 2026