Medical calculators takes an individual patient’s data and uses it in a formula to calculate a Score. Medical calculators simplify complex medical calculations and provide instant analysis of data which can be used in patient care. They are useful in tracking vital signs, calculating drug dosage, interpret lab results and predict risk for an individual patient. The negative side of medical calculators is that If incorrect or wrong data is entered then the score will not be accurate and misinterpreted score can result in over / under investigation, diagnosis and treatment. Hence the use and interpretation of medical calculators should be with caution and under expert guidance. The simplest Medical calculator is Body mass index calculator (BMI) which needs an input of height and weight only. See below for some useful calculators.

• Body mass index calculator (BMI; Quetelet`s index)
• Ideal body weight calculator for adults
• Basal estimated energy expenditure calculator (Harris-Benedict equation) in adults
• PREVENT calculator.
•  ASCVD Risk Estimator Plus (2018) 
• Stroke risk in male patients (55 to 84 yrs.) (Framingham data)
• Stroke risk in female patients (55 to 84 yrs.) (Framingham data)
• GAD -7 anxiety scale in adults.
• Patient Health Questionnaire-2 (PHQ-2)
• Depression screening by a nine-item patient health questionnaire (PHQ- 9) in adults.
• Alcohol consumption screening AUDIT questionnaire in adults.
• CIWA – AR Clinical institute withdrawal assessment for alcohol scale in adults.
• Sleep problem questionnaire in adults.
• Epworth sleepiness scale (ESS) in adults.
• Enhanced STOP – Bang screening questionnaire for obstructive sleep apnoea (OSA) in adults.
• Breast cancer risk assessment by Gail Model 2018
• FIB-4 index, an indirect marker for liver fibrosis in adults.

(calculator.net, MD CALC , PREVENT Online calculator, Med central, Med media, MSD Manuals, National cancer institute, Google)