Free Genetics & Pregnancy Tools
24 calculators you can use right now in your browser, and 32 free tools inside the app for genetics, pregnancy, fertility and baby development.
Free web calculators
These 24 run right here in your browser. Open one and start.
- Ovulation CalculatorOvulation is usually about 14 days before your next period. See your likely ovulation day and six-day fertile window.
- Period CalculatorYour next period is due one cycle length after the last one began. See your next three periods and your ovulation day.
- Implantation CalculatorImplantation happens 6 to 12 days after ovulation, most often on day 8, 9 or 10. See those days for your cycle.
- When to Take a Pregnancy TestTest from the first day of your missed period; a week later is the most reliable. Find both days for your cycle.
- Due Date CalculatorEstimate your delivery date from your last period, conception date, or IVF transfer.
- Twin Due Date CalculatorYour 40-week medical due date, plus the planned-birth target and window for twins by chorionicity, and for triplets.
- Twin Name GeneratorSuggested twin name pairs from official 2025 name lists, scored for syllables, sounds, first letters and popularity.
- Pregnancy Weeks to Months CalculatorTurn weeks pregnant into months, or months into weeks, with a table for every week from 1 to 42.
- Corrected Age CalculatorAdjust a preterm baby's age to their due date — the age milestones and growth charts are read against.
- Baby Percentile CalculatorWeight, length or head circumference against WHO's growth standards, for your baby's exact age in days.
- Baby Age Calculator: Age in Days, Weeks and MonthsYour baby's exact age from the birth date, the next milestone days, and what is typical for sleep and teeth at that age.
- Wake Window Calculator & Baby Sleep ScheduleHow long your baby can stay awake, how many naps to expect, and a sample day built from your baby's wake-up time.
- Baby Teething Chart: Which Teeth Come WhenWhich baby teeth are typical at your baby's age, which could be coming through now, and when to expect the rest.
- Pregnancy Weight Gain CalculatorSee your IOM-recommended weight gain range by pre-pregnancy BMI, week by week — for singleton and twin pregnancies.
- BMI CalculatorFind your BMI and healthy weight range — the number that sets your pregnancy weight-gain targets.
- Caffeine Calculator: Pregnancy & Breastfeeding LimitsTap your sources to total today's caffeine and compare it to the ceiling for where you are: 200 mg a day in pregnancy, 300 while breastfeeding, 400 otherwise.
- Pregnancy Water Intake CalculatorYour daily hydration goal from your weight, your activity level and whether you're carrying twins — floored at the IOM's pregnancy minimum and capped for safety.
- Contraction TimerTap when each contraction starts and stops. Watch for the 5-1-1 rule and know when it's time to head in.
- Hospital Bag ChecklistPack everything you, your partner, and your baby need — customized for your delivery.
- Pregnancy Announcement CardEnter your due date for a card to share: weeks along, your baby's size this week and the month you're due.
- Baby Eye Color PredictorPick each parent's eye color and see the odds for your baby's, with the Punnett squares behind them.
- Baby Zodiac Sign PredictorEnter your due date or conception date to reveal your baby's zodiac sign, element, and key traits — just for fun.
- Mayan Gender PredictorAn ancient parity method: your age and the conception month decide boy or girl — instantly, and just for fun.
- Chinese Gender PredictorA boy-or-girl guess read off the real traditional chart — your dates converted with the Chinese calendar, just for fun.
Genetic Predictors
Eye Color Predictor
Predict baby's eye color using the two-gene inheritance model. Input parent and grandparent eye colors for accurate probability calculations.
Hair Color Predictor
Calculate probable hair color outcomes based on melanin genetics and family inheritance patterns.
Hair Type Predictor
Predict curly, wavy, or straight hair using dominant/recessive gene analysis.
Blood Type Calculator
Determine possible blood types using ABO and Rh factor inheritance rules.
Height Estimator
Calculate predicted height range using mid-parental formula and genetic variance.
Pregnancy Health
Due Date Calculator
Calculate your estimated due date based on last period or conception date.
Pregnancy Weight Gain Calculator
Personalized weight gain recommendations based on your BMI and pregnancy stage.
BMI Calculator
Calculate your pre-pregnancy Body Mass Index.
Fertility & Conception
Ovulation Calculator
Predict your most fertile days.
Fertility Window Tracker
Identify your best days to conceive.
Cycle Length Calculator
Track and analyze your menstrual cycles.
Free Tools FAQ
Common questions about our free tools
Yes! All tools are completely free, no credits required, no subscription needed. Only AI baby photo predictions require credits.
That is the plan, and today every one of the 32 tools works with no credits and no subscription. We would rather be straight with you than promise forever: ProbaBaby is built by one parent — no ads, no investors — and supporters are what keep it free.
Not for the web calculators at the top of this page. A free account is required to use the app — Sign in with Apple, Google, email and password, or an email code; there is no guest mode. The calculators on proba.baby run in your browser and need no account.
Yes! Most tools work offline. Only AI predictions requiring processing need internet.
Free tools use standard calculations. AI predictions use Google Gemini AI and image generation, which cost us per prediction.
Yes. They use established genetic models like the two-gene model for eye color and Mendelian inheritance for blood type. However, these are simplified models.
Access All Free Tools in the App
Download ProbaBaby for all 32 tools in the app — free with a free account; no credits, no subscription.
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