Pregnancy & Gestational
Age Calculator
Calculate your clinical estimated due date (EDD), current gestational week and days, trimester milestones, and baby size estimates. 100% private and calculated locally on your device.
Pregnancy Calculator
Adjusts ovulation date according to your natural follicular phase length.
Baby is the size of a Lime
Vital organs such as the kidneys, intestines, brain, and liver are beginning to function. Tiny fingers and toes are unwebbed.
Available Pregnancy & Gestational Health Tools (7)
Clinical-grade companions for due date calculation, fetal activity tracking, and labor timing
Pregnancy Calculator
Estimate your due date, current gestational week, trimester, and baby size milestone.
Due Date Calculator
Calculate your exact estimated delivery date via LMP, conception date, or IVF transfer.
Weeks Pregnant Calculator
Find out how many weeks and days pregnant you are right now and days remaining.
Conception Date Calculator
Work backwards from your due date or LMP to discover the likely conception window.
Pregnancy Weight Gain Calculator
Track recommended gestational weight gain ranges based on clinical Institute of Medicine (IOM) guidelines.
Baby Kick Counter
Cardiff “Count to 10” protocol with live stopwatch timer and movement timestamp logging.
Contraction Timer & 5-1-1 Rule
One-tap contraction duration and interval tracking with automatic 5-1-1 hospital alert diagnostic.
How to Use the Pregnancy Calculator
A step-by-step guide to calculating gestational milestones based on American College of Obstetricians and Gynecologists standards
Select Dating Methodology
Choose whether to date from your Last Menstrual Period (LMP), Exact Conception Date, or IVF Embryo Transfer Date (Day 3 or Day 5).
Adjust Typical Cycle Length
If your cycle length differs from the 28-day statistical average, adjust the slider or write your number directly. The tool adjusts ovulation by adding or subtracting days from Naegele’s baseline.
Review Gestational Milestones
Read your exact gestational weeks, days remaining until 40 full weeks, trimester marker, upcoming clinical ultrasound windows, and baby size analogies.
Pregnancy Calculator FAQ
Clinical facts on gestational dating, Naegele’s rule, trimester divisions, and data privacy
The standard clinical calculation uses Naegele’s Rule, endorsed by the American College of Obstetricians and Gynecologists (ACOG). It calculates the Estimated Due Date (EDD) by adding 280 days (40 weeks) to the first day of your Last Menstrual Period (LMP). For cycles that differ from the 28-day standard, the formula adjusts by adding (Cycle Length - 28 days) to properly account for follicular phase variance.
According to ACOG Committee Opinion No. 700, a first-trimester ultrasound measurement of the fetal Crown-Rump Length (CRL) up to and including 13 6/7 weeks is the most accurate method to confirm or adjust gestational age. If an ultrasound in the first trimester differs from your LMP date by more than 5 to 7 days, your obstetric provider may adjust your official EDD.
Gestational age is calculated from the first day of your LMP, which is approximately two weeks before ovulation and conception occur. Fetal (conceptional) age measures the actual age of the growing embryo from the moment of fertilization. Therefore, fetal age is typically two weeks younger than gestational age.
- First Trimester: Weeks 1 through 12 (conception, organogenesis, placenta establishment).
- Second Trimester: Weeks 13 through 27 (rapid anatomical growth, anatomy ultrasound scan).
- Third Trimester: Weeks 28 through 40+ (lung maturation, fetal weight gain, preparation for labor).
No. All computations are performed strictly in client-side memory within your web browser. SheCalc does not store, profile, transfer, or upload your menstrual or gestational dates to remote servers.