Free Pregnancy Tool

Pregnancy Due Date Calculator

Find out when your baby is due. Enter your details below and get your estimated due date, pregnancy timeline, week-by-week milestones, and baby size comparisons — instantly.

✓ Based on medical standards
✓ Four calculation methods
✓ Instant results
✓ 100% free

Calculate by Last Menstrual Period

The most common method — used by most healthcare providers.

Calculate by Conception Date

Use this if you know the exact date of conception or ovulation.

Calculate by IVF Transfer Date

For IVF pregnancies — more precise because the conception date is known.

Calculate by Ultrasound Date

Use measurements from an early ultrasound for the best accuracy.

Your Estimated Due Date

📋 Key Dates & Milestones

✨ Fun Facts About Your Baby

How Is Your Due Date Calculated?

A pregnancy due date is an estimate of when your baby will arrive. The most widely used method is Naegele's rule, which adds 280 days (40 weeks) to the first day of your last menstrual period (LMP). This assumes a standard 28-day cycle with ovulation occurring on day 14.

Because not every cycle is 28 days, our calculator adjusts for your actual cycle length. If your cycle is longer or shorter than 28 days, your ovulation day shifts, and so does your estimated due date.

Did you know? Only about 4–5% of babies are born on their exact due date. Most arrive within a two-week window before or after. Think of your due date as a "due estimate" rather than a fixed appointment.

Four Ways to Estimate Your Due Date

  1. Last Menstrual Period (LMP): The standard method. Add 280 days to day one of your last period, adjusted for cycle length.
  2. Conception Date: If you know when you conceived, add 266 days (38 weeks). Conception typically occurs about 14 days after LMP.
  3. IVF Transfer Date: For IVF pregnancies, the due date is calculated from the transfer date minus the embryo age (Day 3 or Day 5), then adding 266 days.
  4. Ultrasound Measurement: An early ultrasound (ideally before 12 weeks) measures your baby and estimates gestational age, which can be used to calculate a due date.

Your Pregnancy Week by Week

Every week of pregnancy brings new developments for your growing baby. Here is a quick reference showing your baby's approximate size (compared to a fruit) and key developmental milestones for each week.

Week 4🌱Poppy Seed — Implantation occurs; embryo has two cell layers
Week 5🫘Sesame Seed — Heart begins to develop
Week 6🫛Sweet Pea — Neural tube closing; heart starts beating
Week 7🫐Blueberry — Brain developing rapidly; arm & leg buds
Week 8🍇Raspberry — Fingers and toes forming; baby moves
Week 9🍒Cherry — All major organs in place
Week 10🍓Strawberry — Vital organs begin functioning
Week 11🫒Fig — Tooth buds appear; can open and close fists
Week 12🍋Lime — Reflexes developing; can make sucking motions
Week 13🍋Lemon — Fingerprints forming; vocal cords developing
Week 14🍑Peach — Can make facial expressions; body growing faster than head
Week 15🍎Apple — Can sense light through closed eyelids
Week 16🥑Avocado — Skeleton hardening from cartilage to bone
Week 17🍐Pear — Fat storage beginning; sweat glands developing
Week 18🫑Bell Pepper — Can hear sounds; you may feel first movements
Week 19🥭Mango — Vernix (protective coating) forming on skin
Week 20🍌Banana — Halfway point! Anatomy scan typically done now
Week 21🥕Carrot — Eyebrows and eyelids fully formed
Week 22🫒Papaya — Sense of touch well developed; lips forming
Week 23🍊Grapefruit — Lungs developing surfactant for breathing
Week 24🌽Corn — Viability milestone; inner ear fully developed
Week 25🥦Cauliflower — Gaining baby fat; skin becoming less translucent
Week 26🥬Lettuce — Eyes begin to open; can respond to sounds
Week 27🥬Cabbage — Can recognize your voice; regular sleep cycles
Week 28🍆Eggplant — Can blink; dreaming (REM sleep) begins
Week 29🎃Butternut Squash — Brain developing rapidly; muscles stronger
Week 30🥥Coconut — Gaining weight steadily; about 3 pounds now
Week 31🍍Pineapple — All five senses are working
Week 32🎃Squash — Practicing breathing movements; toenails growing
Week 33🥒Celery — Bones hardening (except skull); immune system developing
Week 34🍈Cantaloupe — Central nervous system and lungs maturing
Week 35🍈Honeydew — Kidneys fully developed; liver can process waste
Week 36🥬Romaine Lettuce — Gaining about an ounce per day; may drop into pelvis
Week 37🥬Swiss Chard — Considered early term! Lungs are mature
Week 38🥒Leek — Brain and lungs continue maturing; firm grasp
Week 39🍉Watermelon — Full term! Baby is around 7+ pounds and ready
Week 40🎃Pumpkin — Due date week! Average weight 7.5 lbs, length 20 in

Frequently Asked Questions

A due date calculator estimates your baby's arrival based on a standard 280-day (40-week) pregnancy from your last menstrual period. Only about 4–5% of babies are born on their exact due date. Most babies arrive within a two-week window before or after. Your healthcare provider may adjust your date based on ultrasound measurements.

Naegele's rule is the standard method used by doctors: take the first day of your last menstrual period (LMP), add one year, subtract three months, and add seven days. This formula assumes a 28-day cycle with ovulation on day 14. The result equals 280 days (40 weeks) from LMP.

Yes. Your healthcare provider may adjust your due date after a first-trimester ultrasound if the baby's measurements differ from the LMP-based estimate by more than 5–7 days. Due dates are more commonly changed earlier in pregnancy, when ultrasound dating is most accurate.

If you don't remember your last period, you can estimate your due date using the date of conception (if known), your IVF transfer date, or an ultrasound measurement. An early ultrasound (before 12 weeks) is the most accurate alternative method for establishing a due date.

For IVF pregnancies, the due date is calculated from the embryo transfer date. For a Day 3 transfer, add 263 days. For a Day 5 blastocyst transfer, add 261 days. IVF due dates are typically more precise because the conception date is known exactly.

Only about 4–5% of babies are born on their exact estimated due date. However, approximately 80% are born within a two-week window (between 38 and 42 weeks). A "due date" is really a "due estimate" — it marks the middle of a normal delivery window.

Gestational age is counted from the first day of your last menstrual period (LMP), which is about two weeks before conception. Fetal age (embryonic age) is counted from the actual date of conception. Gestational age is always about two weeks more than fetal age. Medical professionals use gestational age as the standard.

According to the American College of Obstetricians and Gynecologists (ACOG): early term is 37–38 weeks, full term is 39–40 weeks, late term is 41 weeks, and post-term is 42 weeks and beyond. Babies born at 39 weeks or later generally have the best health outcomes.

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Medical Disclaimer: This pregnancy due date calculator is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Only about 4–5% of babies arrive on their calculated due date. Always consult your healthcare provider for an accurate assessment of your pregnancy and due date. If you have concerns about your pregnancy, contact your doctor or midwife immediately.