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Biomedical Engineering

Biomedical engineering formulas and calculators for biomechanics and physiological systems modeling used in medical devices and human movement analysis. Includes tissue mechanics, body fluid dynamics, and biosignal equations.

44Formulas

2Subcategories

Updated Oct 2026

All (44) Biomechanics (4) Physiological Systems (40)

Physiological Systems

Glasgow Coma Scale Total Score

GCS = Eye + Verbal + Motor

Physiological Systems

TENS Unit Duty Cycle

Duty cycle (%) = (Pulse width / Pulse period) * 100

Physiological Systems

Medical Device Battery Life Estimate

Life (hr) = Battery capacity (mAh) / Device draw (mA)

Physiological Systems

Ultrasound Axial Resolution

Axial resolution = SPL / 2

Physiological Systems

Pulse Oximeter Perfusion Index

PI = (AC / DC) * 100

Physiological Systems

Insulin Pump Basal Rate

Basal rate (units/hr) = TDD * 0.5 / 24

Physiological Systems

Defibrillator Pediatric Energy Dose

Energy (J) = 2 to 4 J/kg * mass (kg)

Physiological Systems

Hearing Aid Gain

Gain (dB) = Output SPL - Input SPL

Physiological Systems

Hearing Threshold Level Conversion

dB HL = SPL(dB) - Reference SPL at that frequency

Biomechanics

Prosthetic Socket Interface Pressure

P = F / A

Biomechanics

Wheelchair Ramp Slope Ratio

Slope = Rise / Run (ADA max = 1:12)

Biomechanics

Compression Stocking Pressure Gradient

Gradient = P_ankle - P_calf

Physiological Systems

Body Temperature Conversion (°F to °C)

°C = (°F - 32) * 5/9

Physiological Systems

Blood Glucose Unit Conversion

mmol/L = mg/dL / 18.0

Physiological Systems

Nebulizer Medication Dose

Dose (mg) = Concentration (mg/mL) * Volume (mL)

Physiological Systems

Ventilator Tidal Volume (Lung-Protective)

VT = IBW * 6 (to 8) mL/kg

Physiological Systems

Oxygen Cylinder Duration

Duration (min) = (Cylinder_PSI - Safety_PSI) * Conversion_factor / Flow_rate

Physiological Systems

IV Drip Rate (Gravity Infusion)

Drip rate (gtt/min) = (Volume_mL * Drop_factor) / Time_min

Physiological Systems

Estimated VO2 Max (Non-Exercise, Simplified)

VO2max ≈ 15 * (HRmax / HRrest)

Physiological Systems

Body Surface Area (Mosteller Formula)

BSA = sqrt((height_cm * mass_kg) / 3600)

Physiological Systems

Cardiac Output

CO = SV * HR

Physiological Systems

Corrected QT Interval (Bazett's Formula)

QTc = QT / sqrt(RR)

Physiological Systems

Standard Drink Alcohol Units

Units = (volume_mL * %ABV) / 1000

Physiological Systems

Insulin-to-Carbohydrate Ratio Dosing

Insulin dose (units) = carb_grams / insulin_to_carb_ratio

Physiological Systems

Ovulation / Fertile Window Estimate

Ovulation day ≈ Cycle length - 14

Physiological Systems

Blood Alcohol Content (Widmark Formula)

BAC = (alcohol_grams / (mass_kg * r)) * 100 - (0.015 * hours)

Physiological Systems

Pulse Pressure

PP = SBP - DBP

Physiological Systems

Mean Arterial Pressure

MAP = DBP + (1/3)*(SBP - DBP)

Physiological Systems

Creatinine Clearance (Cockcroft-Gault)

CrCl = ((140-age)*mass) / (72*Scr) (×0.85 for women)

Physiological Systems

Glycemic Load

GL = (GI * carb_grams) / 100

Physiological Systems

Daily Protein Requirement

Protein (g) = mass(kg) * factor (factor ≈ 0.8 sedentary, 1.2-2.0 active/athletic)

Physiological Systems

Daily Water Intake Recommendation

Water (mL) = mass(kg) * 30

Physiological Systems

Pregnancy Due Date (Naegele's Rule)

Due date = Last menstrual period + 280 days

Physiological Systems

Body Fat Percentage (U.S. Navy Method, Men)

BF% = 495 / (1.0324 - 0.19077*log10(waist-neck) + 0.15456*log10(height)) - 450

Physiological Systems

Waist-to-Hip Ratio

WHR = waist_circumference / hip_circumference

Physiological Systems

Ideal Body Weight (Devine Formula)

IBW(men) = 50 + 2.3*(height_in - 60); IBW(women) = 45.5 + 2.3*(height_in - 60)

Physiological Systems

Calories Burned During Exercise (MET Formula)

Calories = MET * mass(kg) * duration(hours)

Physiological Systems

Target Heart Rate (Karvonen Formula)

THR = ((HRmax - HRrest) * intensity) + HRrest

Physiological Systems

Estimated Maximum Heart Rate

HRmax = 220 - age

Physiological Systems

Total Daily Energy Expenditure (TDEE)

TDEE = BMR * activity_factor

Physiological Systems

Basal Metabolic Rate (Mifflin-St Jeor)

BMR = 10*mass + 6.25*height - 5*age + s (s = +5 for men, -161 for women)

Physiological Systems

Body Mass Index (BMI)

BMI = mass / height²

Physiological Systems

Poiseuille's Law

Q = πΔPr⁴ / (8ηL)

Biomechanics

Young's Modulus (Tissue)

E = σ / ε