Track Gestational Weeks,
Celebrate Every Milestone.
Free pregnancy calculators: due date by LMP or conception, trimester and week tracking, and IOM weight-gain ranges by pre-pregnancy BMI. Educational and always free. No sign-up.
Naegele's 280-Day Standard
Last menstrual period + 7 days + 9 months: standard obstetric gestational benchmark.
IOM Weight Guidelines
Institute of Medicine pregnancy weight gain targets tailored to pre-pregnancy BMI tiers.
5-1-1 Contraction Rule
Contractions 5 minutes apart, lasting 1 full minute, for 1 hour: the sign to head to the hospital.
PregnancyCalc Calculators
Due Date Calculator
Due date by LMP (with cycle-length adjustment), conception date, or ultrasound — plus current week and days remaining.
Pregnancy Week & Trimester Calculator
Current gestational week, trimester, and milestone dates — from your due date or LMP, matching your clinic's counting.
Pregnancy Weight Gain Calculator
IOM recommended weight-gain ranges by pre-pregnancy BMI — total and by trimester, with singleton and twin guidance.
Contraction Timer
Time contractions and see the pattern — duration, frequency, and the standard hospital guidance thresholds in one place.
Evidence-Based Physiology
How Pregnancy Dating Works: LMP, Ultrasound, and the 280-Day Idea
You are "2 weeks pregnant" at conception, the due date is a 250-year-old rule plus a scan, and 40 weeks is an average. The calendar, explained.
The IOM Weight-Gain Ranges: Where They Came From and How to Use Them
The 2009 guidelines keyed to pre-pregnancy BMI balance newborn birthweight against retention. What the ranges assume, and what "within range" actually means week to week.
Early Labor vs Practice Contractions: A Timing-Based Field Guide
The 5-1-1 rule, the Braxton Hicks tells, and the symptoms that skip the line. What to time, what to watch, and when to call regardless of numbers.