Pregnancy Calculator

Calculate your due date, track pregnancy progress, and view important milestones based on various pregnancy dating methods. Supports multiple calculation methods for accurate pregnancy tracking.

Pregnancy Calculator

Calculate Based On

Your Due Date

Enter your last menstrual period date to calculate pregnancy details.

Understanding Pregnancy Calculations

Pregnancy typically lasts about 40 weeks (280 days) from the last menstrual period (LMP) or 38 weeks from conception. Understanding how pregnancy is calculated and what to expect during each stage helps you prepare for this incredible journey.

How Pregnancy is Calculated

Healthcare providers use gestational age, which starts from the first day of your last menstrual period, even though conception typically occurs about two weeks later. This standardized method ensures consistent tracking across all pregnancies.

Gestational Age

Calculated from the first day of your last menstrual period (LMP). This is the standard used by healthcare providers and includes the two weeks before conception.

Fetal Age

Calculated from conception date, typically 2 weeks less than gestational age. Also called embryonic age or conceptional age.

Due Date Calculation

Estimated as 280 days (40 weeks) from LMP using Naegele's rule. Only 4% of babies are born on their exact due date.

Trimester System

Pregnancy is divided into three trimesters: 1st (weeks 1-12), 2nd (weeks 13-26), and 3rd (weeks 27-40), each with distinct characteristics.

Calculation Methods

Last Menstrual Period (LMP): Most common method, adds 280 days to the first day of your last period
Ultrasound Dating: Most accurate in first trimester (±3-5 days), uses fetal measurements
Conception Date: If known, adds 266 days to conception date or 280 days to LMP equivalent
IVF Transfer Date: Most precise method, calculated from embryo transfer date and embryo age

Important Note: Due dates are estimates. Most babies (85%) are born within 2 weeks of their calculated due date. Full-term pregnancy ranges from 37-42 weeks.

Fetal Development Throughout Pregnancy

Fetal development follows a remarkable and predictable pattern throughout pregnancy. Understanding these developmental milestones helps you appreciate the incredible changes happening during each stage of pregnancy.

First Trimester (Weeks 1-12)

The first trimester is a period of rapid development where all major organs and body systems begin to form. This is the most critical period for fetal development.

Weeks 1-4

Fertilization occurs Implantation in uterus Neural tube begins forming Heart starts developing Size: Poppy seed to lentil

Weeks 5-8

Heart begins beating Limb buds appear Facial features forming Major organs developing Size: Raspberry to grape

Weeks 9-12

All organs present Fingers and toes formed Reflexes developing Gender determination possible Size: Cherry to lime

Second Trimester (Weeks 13-26)

Often called the "golden period" of pregnancy, the second trimester brings rapid growth and the exciting milestone of feeling baby's first movements.

Weeks 13-18

Rapid growth period Sex organs fully developed Baby can hear sounds First movements (quickening) Size: Peach to bell pepper

Weeks 19-26

Brain development accelerates Sleep-wake cycles develop Lungs begin producing surfactant Viability milestone at 24 weeks Size: Banana to eggplant

Third Trimester (Weeks 27-40)

The final stretch focuses on growth and maturation, preparing your baby for life outside the womb.

Weeks 27-32

Eyes can open and close Bones hardening (except skull) Rapid brain development Immune system strengthening Size: Cauliflower to squash

Weeks 33-40

Lungs nearly mature Rapid weight gain Full-term at 37 weeks Ready for birth Size: Pineapple to watermelon

Key Developmental Milestones

Week 6: Heart begins beating (detectable by ultrasound)
Week 8: All major organs present, officially called a fetus
Week 12: Risk of miscarriage significantly decreases
Week 16-20: Gender can be determined, anatomy scan performed
Week 18-22: First movements felt (quickening)
Week 24: Viability milestone - survival possible with medical care
Week 28: Eyes open, rapid brain development
Week 37: Considered full-term, lungs mature

Remember: Every pregnancy is unique. These are average milestones, and your baby may develop slightly ahead or behind these timelines. Always consult with your healthcare provider for personalized information about your pregnancy.

Pregnancy Health & Prenatal Care

Proper prenatal care and healthy lifestyle choices during pregnancy are essential for both maternal and fetal health. Regular medical checkups, proper nutrition, and avoiding harmful substances help ensure the best possible outcomes.

Prenatal Care Schedule

Regular prenatal visits allow healthcare providers to monitor your health and your baby's development, catch potential issues early, and provide guidance throughout your pregnancy.

First Trimester

Initial visit: 8-10 weeks Monthly visits Blood tests and screenings First ultrasound Genetic counseling if needed

Second Trimester

Visits every 4 weeks Anatomy scan (18-22 weeks) Glucose screening (24-28 weeks) Blood pressure monitoring Weight gain assessment

Third Trimester

Every 2 weeks until 36 weeks Weekly visits after 36 weeks Group B strep test Fetal monitoring Birth plan discussion

Important Tests and Screenings

First Trimester Screening (10-13 weeks): Blood test and ultrasound to assess risk for chromosomal abnormalities
Anatomy Scan (18-22 weeks): Detailed ultrasound to check fetal development and detect abnormalities
Glucose Screening (24-28 weeks): Test for gestational diabetes, may require follow-up glucose tolerance test
Group B Strep Test (35-37 weeks): Screening for bacteria that could affect baby during delivery
Non-Stress Test (if needed): Monitors fetal heart rate and movement, typically in high-risk pregnancies

Nutrition and Lifestyle

Essential Nutrients

Folic acid: 400-800 mcg daily Iron: 27 mg daily Calcium: 1000 mg daily DHA: 200-300 mg daily Vitamin D: 600 IU daily

Foods to Avoid

Raw or undercooked meats High-mercury fish Unpasteurized products Excessive caffeine Alcohol and tobacco

Healthy Weight Gain

Underweight: 28-40 lbs Normal weight: 25-35 lbs Overweight: 15-25 lbs Obese: 11-20 lbs

Safe Exercise

Walking and swimming Prenatal yoga Low-impact aerobics Avoid contact sports 30 minutes most days

Warning Signs to Watch For

Severe abdominal pain: Could indicate ectopic pregnancy, placental abruption, or other complications
Heavy bleeding: More than light spotting, especially with cramping
Severe headaches: Persistent headaches, especially with vision changes or swelling
Decreased fetal movement: Significant reduction in baby's movements after 28 weeks
Signs of preterm labor: Regular contractions, pelvic pressure, or fluid leakage before 37 weeks

Emergency Situations: Contact your healthcare provider immediately if you experience severe bleeding, intense abdominal pain, signs of preeclampsia (severe headache, vision changes, upper abdominal pain), or any concerns about your baby's movements.