These calculators support fertility tracking and pregnancy planning — from the Ovulation Calculator and Conception Date Calculator to the Due Date Calculator and Pregnancy Weight Gain Calculator. The Menstrual Period Calculator helps you track your cycle over time, and the collection also includes gestation tools for animals, such as the Rabbit Gestation Calculator and Llama Gestation Calculator, useful for breeders and curious owners alike.
Browse the most-popular list to see which tools visitors reach for most, or open the Trending tab to find what's gaining attention right now. All calculators are free, need no sign-up, and work on any phone, tablet, or desktop.
- Body Composition Calculator
- Metabolism Calculator
- Nutrition Calculator
- Heart Health Calculator
- Pregnancy Calculator
- Fitness Calculator
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Pregnancy Calorie Needs CalculatorEstimate daily calorie needs during pregnancy by trimester. Uses Mifflin-St Jeor TDEE plus standard +340/+452 kcal add-ons. General guidance only.
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Baby Gender Heart Rate PredictorTry the old wives' tale: enter your baby's fetal heart rate and see if the folk rule predicts a boy or a girl. Just for fun — not medical advice.
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Animal Gestation Due Date CalculatorEstimate the due, birth or hatch date of cows, pigs, sheep, goats, horses, dogs, cats and more from a breeding date, or work backward to find a breeding date.
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Dog Pregnancy Week CalculatorFind out what week of pregnancy your dog is in. Enter the breeding date and today's date to track gestation stage out of 9 weeks (≈63 days).
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Fundal Height CalculatorEstimate expected fundal height in cm from gestational age. Get the normal range (weeks ± 2 cm) to compare with a clinical measurement.
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Due Date CalculatorCalculate your due date accurately with this due date calculator. Input your last period and cycle length to determine your expected delivery date. Plan for your baby's arrival with precision.
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Ovulation Date CalculatorEstimate your ovulation day and fertile window from the first day of your last period and your average cycle length. Free, fast, and easy to use.
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Pregnancy Countdown CalculatorCount down to your due date. Enter your due date and today's date to see exactly how many days and weeks are left until your baby arrives.
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Gestation CalculatorEstimate the due date by adding a gestation period (in days) to the conception date. Works for humans and animals with custom gestation lengths.
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Pregnancy Week-by-Week CalculatorFind out how many weeks pregnant you are using your last menstrual period (LMP). See your gestational age, trimester, and days until your due date.
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Safe Period (Rhythm) CalculatorEstimate your safe days and fertile window using the rhythm (calendar) method. Find low-fertility days based on your average menstrual cycle length.
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Chinese Gender Predictor CalculatorPredict baby boy or girl with the traditional Chinese gender calendar using mother's lunar age and the lunar conception month. For fun only.
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Contraction Timer & Frequency CalculatorCalculate labor contraction frequency and duration from start and end times. Find how far apart contractions are and how long each lasts.
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Trimester CalculatorFind out which pregnancy trimester you are in based on your last menstrual period (LMP). Get your gestational week and days until your due date.
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hCG Doubling Time CalculatorCalculate hCG doubling time, total percent change, and rate of rise per day from two beta hCG blood test results taken hours apart.
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Pre-Pregnancy BMI & Weight Gain CalculatorCalculate your pre-pregnancy BMI and see the recommended total weight gain range for a healthy single pregnancy based on IOM guidelines.
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Baby Wake Window CalculatorFind your baby's next nap or bedtime. Enter age and last wake-up time to get an age-appropriate wake window and recommended sleep time.
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Weeks Until Due Date CalculatorFind how many weeks are left until your due date. Enter your due date and today's date to see weeks and days remaining and your approximate gestational age.
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Postpartum Weight Loss CalculatorEstimate how many weeks to reach your goal weight after birth using safe loss rates (~0.5 kg/week if breastfeeding). General guidance only.
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Pregnancy Water Intake CalculatorEstimate your daily water needs during pregnancy or breastfeeding based on body weight and exercise. Get results in liters, cups and fluid ounces.
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Breast Milk Storage Time CalculatorFind out how long freshly pumped breast milk stays safe. Enter the pump time and storage location to get the safe-until date for room, fridge or freezer.
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Newborn Weight Loss Percentage CalculatorCalculate your newborn's weight loss percentage from birth weight and current weight. See if it exceeds the 10% pediatric concern threshold.
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Weeks Pregnant CalculatorFind out how many weeks pregnant you are today. Calculate gestational age in weeks and days from your last menstrual period (LMP) date.
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Pregnancy Trimester End Dates CalculatorCalculate the start and end dates of each pregnancy trimester and your estimated due date from your last menstrual period (LMP) and cycle length.
Frequently asked questions
What can I calculate in this category?
You can estimate your due date, find likely conception dates, predict upcoming ovulation windows, track your menstrual cycle across months, and monitor healthy weight gain during pregnancy. The animal gestation tools calculate expected birth dates for rabbits, llamas, and other species based on their typical gestation periods.
How accurate are the due date and ovulation estimates?
Dates are calculated using standard obstetric methods — for example, Naegele's rule for due dates and average cycle-length models for ovulation windows. Results are estimates; actual dates vary between individuals. These tools are NOT medical advice — consult a qualified healthcare professional or midwife for guidance throughout your pregnancy.
Do the animal gestation calculators use real biological data?
Yes — each calculator is based on the documented average gestation length for that species (roughly 31 days for rabbits, approximately 350 days for llamas). They provide a practical planning aid for breeders and owners, but individual variation is always normal.
Do you store personal health information I enter?
No. All calculations run in your browser. Last menstrual period dates, cycle lengths, and other personal details are never sent to our servers or retained after you close the page.
Which pregnancy calculators are most popular?
The list is ranked by real visitor usage, reflecting which tools people find most useful. Switch to the Trending tab to see what's seeing the fastest growth right now, or Recently Added for the newest arrivals.
