Medical calculators

This is a collection of popular medical calculators. Also check out MedCalc for other useful calculators.

#Body Mass Index (BMI)

Source: World Health Organization

BMI is a simple index of weight-for-height that is commonly used to classify underweight, overweight, and obesity in adults. It provides a useful population-level measure of overweight and obesity. However, BMI does not differentiate between body fat and muscle mass, so it's not a perfect measure.

Range Classification
< 18.5 Underweight
18.5-25 Normal
25-30 Overweight
30-35 Obese Class I (Moderate)
35-40 Obese Class II (Severe)
≥ 40 Obese Class III (Very severe or morbidly obese)

#Body Surface Area (Mosteller)

Source: Mosteller RD (1987)

The Mosteller formula is a commonly used method to calculate Body Surface Area, which is a measurement used in many medical tasks.


#Corrected Calcium based on Albumin

Source: Payne RB, et al. (1973)

Calcium levels in the blood can be affected by albumin levels, as calcium binds to albumin. Correcting calcium based on albumin provides a more accurate representation of calcium levels in various clinical scenarios.


#Corrected QT Interval

Source: Bazett HC (1920)

Source: Dmitrienke AA, et al. (2005)

Source: Fridericia LS (1920)

Source: Sagie A, et al. (1992, Framingham)

Source: Hodges MS, et al. (1983)

Source: Rautaharju PM, et al. (2014)

Calculates the corrected QT interval using various methods.

Category Males Females
Normal ≤ 440 ms ≤ 450 ms
Borderline 441-450 ms 451-460 ms
Prolonged > 450 ms > 460 ms
High Torsades de pointes risk > 500 ms > 500 ms

#Corrected Sodium for Hyperglycaemia

Source: Katz MA (1973)

Source: Hillier TA, et al. (1999)

Corrects serum sodium levels based on elevated blood glucose levels using various methods. Values are rounded to the nearest integer.


#Cycle Time to Heart Rate

Converts cycle time in milliseconds (ms) to heart rate in beats per minute (BPM) rounded to the nearest integer.


#Heart Rate to Cycle Time

Converts heart rate in beats per minute (BPM) to cycle time in milliseconds (ms).


#LDL Calculation (Friedewald Equation)

Source: Friedewald WT, Levy RI and Fredrickson DS (1972)

Estimates LDL cholesterol using the Friedewald equation, which requires total cholesterol, HDL cholesterol, and triglycerides.

LDL Level (mg/dL) Interpretation
< 100 Optimal
100-130 Near/Above Optimal
130-160 Borderline High
160-190 High
≥ 190 Very High

#MDRD GFR Equation

Source: Levey AS, et al. (1999)

The MDRD formula is a widely used equation to estimate the glomerular filtration rate based on serum creatinine, age, and race.


#Mean Arterial Pressure (MAP)

The MAP is an average blood pressure in an individual. It's used to give a general overview of blood flow and perfusion. A normal MAP is usually 70-110 mmHg.