Pregnancy Due Date Calculator

How Is Your Pregnancy Due Date Calculated?

The most common method to calculate your due date is Naegele’s rule, developed by German obstetrician Franz Karl Naegele in the early 1800s. It is still the medical standard today: take the first day of your last menstrual period (LMP), add one year, subtract three months, and add seven days. The result is your estimated due date (EDD) — about 280 days (40 weeks) from the start of your last period.

5 Calculation Methods Explained

1. Last Menstrual Period (LMP): The default method. Adds 280 days to the first day of your last period. Best when you have regular cycles.
2. Conception Date: If you know exactly when you conceived (for example through ovulation tracking), the calculator adds 266 days to that date. Most accurate for planned conception.
3. IVF 3-day Transfer: The embryo is transferred 3 days after fertilization. Add 263 days to the transfer date.
4. IVF 5-day Transfer: The blastocyst is transferred 5 days after fertilization. Add 261 days to the transfer date.
5. Ultrasound Dating: A first-trimester ultrasound measures crown-rump length (CRL) to estimate gestational age, then your due date is back-calculated. This is considered the most accurate method when done between weeks 8 and 13.

How Accurate Is the Due Date?

Only about 4-5% of babies are born on their exact due date. Most arrive within two weeks before or after — which is medically considered “term.” Babies born between 37 and 42 weeks are considered full-term. Your due date is a guide, not a deadline. For a complete pregnancy wellness profile, also try our free Body Shape Calculator for female to track healthy proportions throughout pregnancy.

When Does the Baby’s Heart Start Beating?

One of the most beautiful moments in early pregnancy is the first detection of your baby’s heartbeat. The fetal heart begins forming as early as week 4, and the first electrical activity — the very first heartbeat — usually starts around week 5 to 6 of pregnancy. At this stage, the heart is just a tiny tube with a steady rhythm of around 90 to 110 beats per minute.

The heartbeat is usually first detectable on a transvaginal ultrasound between weeks 6 and 7. By week 9, the heart has developed all four chambers and reaches its peak rate of 160 to 180 BPM. After this peak, the heart rate gradually settles as the baby grows — by the third trimester, the typical range is 110 to 150 BPM, closer to a newborn’s heart rate.

Pregnancy brings many beautiful changes — including subtle face shape adjustments due to swelling and hormonal shifts. Use our free Face Shape Calculator for female for hairstyle and styling tips that flatter pregnancy face changes.

What If You Don’t Hear a Heartbeat at the First Scan?

Sometimes a heartbeat isn’t detected at the first scan, especially if it is very early (before week 6) or if the baby is positioned awkwardly. This does not always mean something is wrong — your doctor will usually schedule a follow-up scan a week or two later. Always discuss any concerns directly with your healthcare provider.

Baby Heartbeat by Week — Complete Timeline

Track your baby’s expected heart rate week by week. Heart rates are general ranges from medical literature — your doctor will confirm your baby’s specific rate during ultrasound. Pair this with our free Body Shape Calculator for female to track healthy pregnancy weight gain proportions.

Boy or Girl by Heartbeat — Myths vs Facts

One of the most popular pregnancy myths claims that a heart rate above 140 BPM means a girl, and below 140 means a boy. This belief has been passed down for generations — but is it true?

What the Science Actually Says

Multiple peer-reviewed medical studies — including a well-known 2006 study published in the Journal of Ultrasound in Medicine — have shown that there is no statistically significant difference between male and female fetal heart rates, especially in the first trimester. The myth has been thoroughly debunked.

What Heartbeat Actually Tells You

• Pregnancy viability: A strong, regular heartbeat is one of the best indicators of a healthy early pregnancy.
• Gestational age: Combined with ultrasound measurements, the heart rate helps confirm pregnancy timeline.
• Possible concerns: A heart rate consistently outside the normal range may prompt further investigation by your doctor.

How to Find Out Baby’s Gender Reliably

For accurate gender identification, doctors use ultrasound imaging at the anatomy scan around weeks 18-20, or NIPT blood tests after week 10. Heart rate is not a reliable indicator.

Pregnancy Week-by-Week Guide

Your 40-week pregnancy journey at a glance. Each phase brings new development for your baby and changes for you. To support your wellness through pregnancy, also check our free Face Shape Calculator for female for personalized hairstyle and styling tips that flatter pregnancy face changes.

Pregnancy Trimester Guide

Pregnancy is divided into three trimesters, each with distinct changes for both you and your baby.

First Trimester (Weeks 1-12)

The most critical period for fetal development. All major organs form during this time. Common symptoms: morning sickness, fatigue, breast tenderness, mood swings. Key milestones: first heartbeat (week 5-6), end of organogenesis (week 12).

Second Trimester (Weeks 13-26)

Often called the “honeymoon trimester” — energy returns and morning sickness fades. Common changes: visible bump, first kicks (around week 18-22), increased appetite. Key milestones: anatomy scan (week 18-22), gender reveal possible, viability milestone (week 24).

Body shape changes most dramatically in the second trimester — track your healthy proportions with our free Body Shape Calculator as your bump grows.

Third Trimester (Weeks 27-40)

Final stretch before birth. Baby gains most of its weight in this period. Common symptoms: back pain, swelling, frequent urination, Braxton Hicks contractions. Key milestones: baby turns head-down, lungs mature, full term reached at week 37.

How to Hear Your Baby’s Heartbeat at Home

Many expecting mothers want to hear their baby’s heartbeat between doctor visits. Here are the safest, most reliable ways:

Fetal Doppler (After Week 12)

A handheld ultrasound device that detects the heartbeat through the abdomen. Reliable from week 12 onwards, when the baby is large enough. Important: home Dopplers are not as accurate as medical ones — not finding a heartbeat at home does not necessarily mean a problem.

Stethoscope (After Week 20)

A regular stethoscope can sometimes pick up the heartbeat after week 20, especially with a slim build. Place it on the lower abdomen and listen patiently. The sound resembles a fast horse gallop.

When to Worry

Always contact your doctor if you have any concerns about heartbeat or baby movement, especially in the third trimester. Reduced fetal movement, sudden changes, or persistent absence of detectable heartbeat at home should prompt a clinic visit. Never use this calculator or any home device as a replacement for professional medical assessment.