Medical Health Calculators
Free blood pressure, dosage, and clinical health tools. Interpret your readings and calculate safe medication doses using AHA, WHO, and FDA guidelines.
Medical Health Calculators - Understand Your Clinical Numbers
Your blood pressure, heart rate, and other clinical readings carry specific meaning only when compared against validated medical guidelines. These calculators apply the latest American Heart Association (AHA) and World Health Organization (WHO) classifications to help you interpret your numbers in context.
Three Medical Calculators
Dosage Calculator - Calculate medication dose by body weight using the mg/kg formula. Enter weight (lbs or kg), the prescribed mg/kg rate, and dosing frequency. Outputs single dose in mg, total daily dose, and suspension volume in mL for five common liquid concentrations.
BAC Calculator - Estimate your blood alcohol content using the Widmark formula. Enter gender, weight, number of standard drinks, and hours since drinking to get your estimated BAC, impairment level, and time until fully sober.
Blood Pressure Calculator - Enter your systolic and diastolic reading to get your AHA 2017 classification (Normal, Elevated, Stage 1, Stage 2, or Hypertensive Crisis), Mean Arterial Pressure, Pulse Pressure, and heart rate category. Average Multiple Readings mode accepts up to 5 measurements and classifies the average for more accurate assessment.
Understanding Blood Pressure Readings
A blood pressure reading has two numbers: systolic (the top number, pressure when your heart beats) and diastolic (the bottom number, pressure between beats). The AHA 2017 guidelines lowered the threshold for high blood pressure Stage 1 from 140/90 to 130/80, meaning significantly more adults now fall into an at-risk category. Regular monitoring with consistent technique matters more than any single reading.
Frequently Asked Questions
When should I check my blood pressure?
For most adults, morning readings before medication and evening readings before dinner provide the most consistent data. Avoid caffeine, exercise, and smoking for 30 minutes before measuring. Sit quietly for 5 minutes, feet flat on the floor, arm at heart level. Take two readings one minute apart and record the average.
What is white-coat hypertension?
White-coat hypertension is elevated blood pressure in a medical setting that is normal at home. It affects 15-30% of patients. Home monitoring with a validated device over several weeks gives a more accurate picture than a single clinic reading. The Blood Pressure Calculator's Average Multiple Readings mode is designed for this kind of tracking.