Six evidence-based health calculators — BMI, blood pressure, 10-year heart risk, water intake, pediatric dosage, and pregnancy due date. All free, no sign-up required.
Free BMI Calculator
Body Mass Index — imperial or metric
Your BMI Result
Enter your height and weight to calculate your BMI.
Fill in your details to calculate your cardiovascular risk.
Free Daily Water Intake Calculator
Personalized hydration goal based on weight, activity, and climate
Your Daily Water Goal
Enter your details to calculate your daily hydration goal.
Free Pediatric Dosage Calculator
Weight-based dosing estimates for common OTC medications
⚠️ Always verify dosing with your child's pediatrician or pharmacist before administering any medication.
Dosage Recommendation
Enter your child's weight to calculate the recommended dose.
Free Pregnancy Due Date Calculator
Naegele's rule — standard OB/GYN calculation
Your Estimated Due Date
Enter your dates above to calculate your due date.
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About Herbafama's Free Health Calculators
All six calculators on this page use validated, evidence-based formulas from established medical authorities — the WHO, CDC, American Heart Association, and National Heart, Lung, and Blood Institute. They provide instant results with no account required and work on any device.
BMI Calculator — Beyond the Number
Herbafama's free BMI calculator uses the standard WHO formula and provides your BMI category based on CDC guidelines. BMI is useful as an initial screening metric — but the American Medical Association now formally acknowledges its limitations, particularly its inability to distinguish muscle from fat and its documented racial bias in threshold setting.
For a complete weight-related health assessment, combine your BMI with waist circumference (men: below 40 inches, women: below 35 inches) and metabolic blood markers. Learn more in our complete BMI guide.
Blood Pressure Checker — AHA 2017 Guidelines
Our blood pressure checker uses the 2017 American Heart Association guidelines — the most current clinical standard. These guidelines lowered the Stage 1 hypertension threshold from 140/90 to 130/80, reclassifying millions of people from "prehypertensive" to "hypertensive." Understanding what your blood pressure numbers really mean is the first step to managing cardiovascular risk.
Remember: a single reading is not a diagnosis. Measure at the same time each morning after 5 minutes of rest, and average readings over 5–7 days. Home monitoring consistently outperforms single clinic readings for accuracy. Read our guide on how to lower blood pressure naturally.
10-Year Heart Risk Calculator — Framingham Score
The Framingham Risk Score is the gold-standard cardiovascular risk prediction tool used by cardiologists worldwide. Validated in large, long-term cohort studies, it estimates your probability of experiencing a major cardiovascular event (heart attack or stroke) over the next 10 years. Use your score to guide conversations with your physician about preventive interventions. See our full guide on reducing your risk of heart disease.
The BMI calculation itself is mathematically precise — it uses the standard WHO formula (weight in kg ÷ height in m²). The health interpretation is based on CDC/WHO BMI categories. Note that BMI is a screening tool, not a diagnostic measure — it cannot distinguish muscle from fat or assess fat distribution.
Normal blood pressure is below 120/80 mmHg according to 2017 AHA guidelines. Elevated is 120-129 systolic with diastolic below 80. Stage 1 hypertension is 130-139/80-89. Stage 2 hypertension is 140/90 or higher. A hypertensive crisis (above 180/120) requires emergency care.
The Framingham Risk Score uses age, sex, total cholesterol, HDL cholesterol, systolic blood pressure, smoking status, and diabetes status to estimate your 10-year risk of a cardiovascular event. It is validated for adults aged 30-74 years without pre-existing cardiovascular disease.
The commonly cited 8 glasses per day is an oversimplification. Actual needs depend on body weight, activity level, climate, and health conditions. Herbafama's water intake calculator uses the formula of body weight (lbs) ÷ 2 in ounces, adjusted for activity and climate — then converts to liters and cups.
Herbafama's pediatric dosage calculator provides weight-based estimates for common OTC medications. These are educational estimates only — always verify doses with your child's pediatrician or pharmacist, particularly for children under 2 years, children with medical conditions, or when using prescription medications.
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⚕️ All calculators are for educational purposes only and are not a substitute for professional medical advice. Consult a licensed healthcare provider before making health decisions based on these results.