ACOG STANDARDS • 100% PRIVATE CLIENT CALCULATION
Women’s Reproductive &
Gestational Health Calculators
Clinical-grade calculation tools for menstrual cycle estimation and gestational milestone tracking. Private, verified, and calculated locally on your device.
Zero Storage
100% On-Device
ACOG Formula
Naegele’s Rule
Instant Run
Fast & Accurate
Period Calculator
Estimate your next menstrual period, calculate ovulation dates, identify peak fertile windows, and review cycle phase breakdown with custom bleeding duration.
100% Private Browser Tool
Open Calculator
Pregnancy Calculator
Calculate your clinical estimated delivery date (EDD) via LMP, Conception Date, or IVF Embryo Transfer. Track current gestational age, trimesters, and baby size milestones.
100% Private Browser Tool
Open Calculator
Frequently Asked Questions
Evidence-based answers on reproductive calculation algorithms and data privacy
The calculator calculates ovulation by subtracting 14 days (the standard luteal phase length) from your total cycle length. Because viable sperm can survive in the reproductive tract for up to 5 days and an egg survives up to 24 hours, the 6-day fertile window covers the 5 days leading up to ovulation plus ovulation day itself.
We implement Naegele’s Rule, endorsed by the American College of Obstetricians and Gynecologists (ACOG). It counts 280 days (40 full gestational weeks) from the first day of your last normal menstrual period (LMP), adjusting for cycle lengths other than 28 days to provide an accurate delivery date.
No. SheCalc runs strictly client-side within your device’s browser memory. Your menstrual cycle dates, conception details, or pregnancy metrics are never transmitted, stored on any remote cloud database, or shared with third parties.
Yes. Our dedicated calculator suites feature customizable cycle lengths from 21 up to 45 days. If your cycles vary significantly from month to month, an obstetric ultrasound in the first trimester (CRL measurement) provides the most definitive gestational dating.