Every calculator you'll
ever need.
All 21 calculators are free to use, no signup needed, from ovulation and due dates to gestational age, weight gain and fun gender predictors. Join Belly Weekly for the weekly email too.
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Conception, Cycle & Gender
Ovulation & Fertility Calendar
FreeMap your fertile window and best days to try.
Fertile Days & Ovulation
FreeYour most fertile days, on a calendar.
Safe Days Calendar
FreeSee your lower-chance days across your cycle.
Date of Conception
FreeEstimate when conception likely happened.
Chinese Baby Gender
FreeThe classic Chinese gender chart — just for fun.
Gender by Parent Blood Type
FreePredict baby's gender from blood types.
Gender by Rh Factor
FreeGender prediction from parents' Rh factor.
Gender by Blood Renewal
FreeThe blood-renewal method prediction.
Pregnancy Tracking & Health
Pregnancy Due Date
FreeYour estimated due date from your last period.
How Many Weeks Pregnant
FreeExactly how far along you are, today.
Pregnancy By Week
FreeWhat's happening this week, for you and baby.
Gestational Age (AOG)
FreeCalculate gestational age from your dates.
Weekly Pregnancy Weight Gain
FreeHealthy weight-gain targets, week by week.
Gestational Diabetes Diet
FreePlan balanced meals if you're managing GD.
Crown-Rump Length (CRL)
FreeEstimate gestation from CRL measurements.
Ultrasound Gestation Period
FreeDate the pregnancy from ultrasound data.
Baby & Newborn
Baby Eye Color
FreeA fun guess at baby's eye color from parents'.
Infant Nutrition Needs (Under 1)
FreeDaily nutrition guidance for baby's first year.
Infant Feeding Volume
FreeHow much milk baby needs per feed, by weight.
Child Development Tracker
FreeMilestones to watch for, month by month.
Child Height & Weight
FreeSee how baby's growth tracks on the charts.