Pregnancy & Fertility Calculators
Track your pregnancy milestones with our free pregnancy and fertility calculators. From estimating your due date to monitoring key developmental stages, our medically-informed tools provide helpful guidance throughout your pregnancy journey.
Pregnancy Calculator
Track your pregnancy week by week and estimate key milestones and your due date.
Due Date Calculator
Calculate your estimated due date based on your last menstrual period or conception date.
Conception Calculator
Estimate your conception date based on your due date or last menstrual period.
Pregnancy Conception Calculator
Calculate when you likely conceived and find your most fertile days for family planning.
Ovulation Calculator
Predict your ovulation dates and fertile window to help with conception planning.
Period Calculator
Track and predict your menstrual cycle dates based on your average cycle length.
Pregnancy Weight Gain Calculator
Track healthy weight gain during pregnancy based on your pre-pregnancy BMI and trimester.
Baby Height Calculator
Predict your baby's future adult height based on parent heights and growth percentiles.
Baby Weight Calculator
Track your baby's weight against growth charts and WHO percentile standards.
How to Choose the Right Pregnancy Calculator
Our pregnancy calculator is designed to provide a comprehensive overview of your pregnancy timeline. If you know the first day of your last menstrual period (LMP), the calculator can estimate your due date, current week of pregnancy, and which trimester you are in.
Keep in mind that due date calculations are estimates. Only about 5% of babies arrive on their exact due date. Most full-term births occur between 39 and 41 weeks of gestation. Your healthcare provider may adjust your estimated due date based on ultrasound measurements, especially during the first trimester when dating is most accurate.
Use the pregnancy calculator as a helpful planning tool, but always follow the guidance of your obstetrician, midwife, or other qualified healthcare provider for all medical decisions during your pregnancy.
Understanding Pregnancy Timelines and Milestones
Pregnancy is typically measured from the first day of the last menstrual period (LMP) and lasts approximately 40 weeks (280 days), divided into three trimesters. This dating convention means that conception usually occurs around week 2, and the first two weeks of pregnancy technically occur before the egg is fertilized.
The first trimester (weeks 1 through 12) is a period of rapid development. By the end of week 8, all major organs have begun forming. This is also when many pregnancy symptoms like morning sickness, fatigue, and breast tenderness are most pronounced. Most healthcare providers recommend the first prenatal visit between weeks 8 and 10.
The second trimester (weeks 13 through 26) is often considered the most comfortable period. Morning sickness typically subsides, and the risk of miscarriage decreases significantly. Fetal movement (quickening) is usually first felt between weeks 16 and 22. The anatomy scan ultrasound, typically performed around week 20, provides detailed assessment of fetal development.
The third trimester (weeks 27 through 40) brings rapid fetal growth and preparation for birth. The baby gains most of its weight during this period. Prenatal visits increase in frequency, typically every two weeks from week 28 and weekly from week 36. Babies born after 37 weeks are considered early term, with full term defined as 39 to 40 weeks.
Frequently Asked Questions
How is my due date calculated?
Due dates are most commonly calculated using Naegele's rule: add 280 days (40 weeks) to the first day of your last menstrual period (LMP). This assumes a 28-day cycle with ovulation on day 14. If your cycles are longer or shorter, the estimate may need adjustment. Ultrasound measurements in the first trimester can provide a more precise estimate and your healthcare provider may revise your due date based on these results.
How accurate is a due date calculator?
Due date calculators provide an estimate based on averages. Only about 5% of babies are born on their exact due date. About 80% of births occur between 37 and 42 weeks of gestation. First-trimester ultrasound dating is accurate to within about 5 to 7 days, while LMP-based calculations can vary more depending on cycle regularity. Your due date is best understood as the midpoint of a likely delivery window.
What are the three trimesters of pregnancy?
Pregnancy is divided into three trimesters, each lasting approximately 13 weeks. The first trimester (weeks 1 to 12) involves major organ development and common symptoms like nausea and fatigue. The second trimester (weeks 13 to 26) brings fetal movement and the anatomy ultrasound. The third trimester (weeks 27 to 40) involves rapid growth and preparation for birth.
When should I schedule my first prenatal appointment?
Most healthcare providers recommend scheduling your first prenatal visit between 8 and 10 weeks of pregnancy. This visit typically includes a health history review, physical exam, blood tests, and possibly an early ultrasound to confirm the pregnancy and estimate gestational age. If you have a high-risk condition or history of complications, your provider may want to see you earlier.