Clinical scale calculators by specialty
44 validated clinical scales and formulas for physicians. Grouped by specialty, with source citations and open formula code
What are clinical scales
Clinical scales and calculators are standardized tools that translate symptoms, lab values, and exam findings into a numerical risk or severity score. Scales support decisions on invasive strategy (GRACE, TIMI), anticoagulation (CHA₂DS₂-VASc, HAS-BLED), pneumonia management (CURB-65), stroke severity (NIHSS), and cirrhosis staging (MELD, Child-Pugh). This page lists every published scale on the site. Every formula is covered by unit tests with reference values from the original publications.
Cardiology8
CHA₂DS₂-VASc calculator online: stroke risk in atrial fibrillation
CHA₂DS₂-VASc score for annual ischemic stroke and systemic embolism risk in non-valvular atrial fibrillation. Includes 7 components: heart failure, hypertension, age, diabetes, prior stroke/TIA, vascular disease, female sex. Guides oral anticoagulation decisions.
CardiologyNeurologyGeneral practice and internal medicineGRACE 2.0 in-hospital mortality risk for ACS
In-hospital mortality risk in acute coronary syndrome from 8 parameters. Used to select timing of invasive strategy.
CardiologyGeneral practice and internal medicineHAS-BLED (Bleeding Risk on Anticoagulation)
Bleeding risk in patients on anticoagulation. Used alongside CHA₂DS₂-VASc.
CardiologyGeneral practice and internal medicineLDL Friedewald calculator online: cholesterol calculation for lipid panel
LDL by Friedewald: LDL = TC – HDL – TG/2.2 (mmol/L) or TG/5 (mg/dL). Used in cardiology and primary care for cardiovascular risk stratification when direct LDL is unavailable.
CardiologyGeneral practice and internal medicineEndocrinologyMAP calculator online: mean arterial pressure formula and shock targets
Mean arterial pressure from systolic and diastolic: MAP = (SBP + 2 × DBP)/3. Tissue perfusion marker used in anesthesia, critical care, sepsis, and shock for hemodynamic management.
CardiologyGeneral practice and internal medicineQTc Bazett calculator online: heart-rate corrected QT interval
Heart-rate corrected QT interval by Bazett formula: QTc = QT/√RR. Used to assess risk of life-threatening arrhythmias (torsade de pointes), when prescribing QT-prolonging drugs, and in long QT syndromes.
CardiologyGeneral practice and internal medicineTIMI Risk Score for UA/NSTEMI
14-day risk of death, MI, or severe ischemia in non-ST-elevation ACS using 7 criteria.
CardiologyGeneral practice and internal medicineWells score for DVT online: deep vein thrombosis probability calculator
Pretest probability of lower-extremity deep vein thrombosis using 9 clinical Wells criteria. Output: low, moderate, or high DVT probability – guides D-dimer and venous ultrasound decisions.
CardiologyGeneral practice and internal medicinePulmonology
Neurology2
Glasgow Coma Scale (GCS)
Consciousness level by eye opening, verbal response, and motor response. Total range 3–15.
NeurologyGeneral practice and internal medicineNIH Stroke Scale (NIHSS)
Standardized 15-item assessment of ischemic stroke severity. Total range 0–42.
NeurologyGeneral practice and internal medicine
Nephrology5
Albumin-Corrected Calcium
Serum calcium corrected for albumin concentration.
NephrologyEndocrinologyGeneral practice and internal medicineAnion Gap (Albumin-Corrected)
Anion gap calculation for differential diagnosis of metabolic acidosis.
NephrologyGeneral practice and internal medicineCreatinine Clearance (Cockcroft-Gault)
Creatinine clearance for drug dose adjustment. Not equivalent to eGFR.
NephrologyGeneral practice and internal medicineOncologyeGFR calculator online: CKD-EPI 2021 formula without race coefficient
Estimated glomerular filtration rate by the updated CKD-EPI 2021 formula without race coefficient. Used in nephrology, cardiology, and endocrinology for CKD staging and drug dose adjustment in adults.
NephrologyGeneral practice and internal medicineCardiologySerum osmolality calculator online: hyponatremia and toxic alcohol workup
Serum osmolality from sodium, glucose, and urea. Used to differentiate hypo- and hypernatremia and to calculate the osmolar gap when methanol, ethylene glycol, or isopropanol poisoning is suspected. Reference range 275–295 mOsm/kg.
NephrologyGeneral practice and internal medicine
Gastroenterology and hepatology3
Child-Pugh Score (Liver Cirrhosis)
Liver cirrhosis severity and survival prognosis assessment.
Gastroenterology and hepatologyFIB-4 calculator online: non-invasive liver fibrosis assessment from biochemistry and platelets
FIB-4 index for screening advanced liver fibrosis (F3–F4) in NAFLD, HCV, HBV, and alcoholic liver disease. Formula: (age × AST) / (platelets × √ALT). >3.25 indicates high probability of advanced fibrosis – elastography or biopsy is warranted.
Gastroenterology and hepatologyGeneral practice and internal medicineFamily medicineMELD Score (Liver Disease)
Chronic liver disease severity and 90-day mortality prognosis.
Gastroenterology and hepatologyNephrology
Endocrinology8
Body fat percentage (US Navy method)
Body fat percentage from neck, waist, and hip circumferences. Validated against hydrostatic weighing.
General practice and internal medicineEndocrinologyBody Mass Index (BMI)
Body mass index from height and weight with WHO classification.
General practice and internal medicineFamily medicineEndocrinologyFINDRISC calculator online: 10-year type 2 diabetes risk assessment
FINDRISC questionnaire for 10-year type 2 diabetes risk screening without lab tests. 8 factors: age, BMI, waist circumference, physical activity, vegetable intake, antihypertensives, prior hyperglycemia, family history. Used in primary care and check-ups.
EndocrinologyGeneral practice and internal medicineFamily medicineHbA1c → estimated average glucose (eAG)
Conversion of HbA1c to average plasma glucose using ADAG equations. Supports NGSP (%) and IFCC (mmol/mol) units.
EndocrinologyGeneral practice and internal medicineFamily medicineHealthy weight range
Weight range by BMI 18.5–24.9 (WHO) plus Devine and Hamwi ideal body weight for drug dosing.
General practice and internal medicineEndocrinologyFamily medicineHOMA-IR calculator online: insulin resistance index, formula, reference ranges
HOMA-IR calculator using the original Matthews 1985 formula. Enter fasting insulin (µU/mL) and fasting glucose (mmol/L or mg/dL) – the tool returns the index plus interpretation by clinical cutoffs: normal (< 2.0), early resistance (2.0–2.9), significant resistance (≥ 3.0).
EndocrinologyGeneral practice and internal medicineObstetrics and gynecologyResting Metabolic Rate (Mifflin-St Jeor) + TDEE
Resting metabolic rate and total daily energy expenditure by activity level. Most accurate formula for adults per ADA Evidence Analysis.
EndocrinologyGeneral practice and internal medicineFamily medicineWeight loss calorie calculator online: daily intake by Mifflin–St Jeor formula
Daily calorie intake for safe weight loss. Based on Mifflin–St Jeor (1990) basal metabolic rate adjusted for activity level and a target 10–25% deficit. Shows daily calories and expected weight loss rate.
EndocrinologyGeneral practice and internal medicineFamily medicine
Pulmonology3
CURB-65 calculator online: community-acquired pneumonia severity in adults
Severity score for adult community-acquired pneumonia. Components: confusion, urea >7 mmol/L, respiratory rate ≥30/min, blood pressure, and age ≥65. Guides treatment setting: outpatient, ward, or ICU.
PulmonologyGeneral practice and internal medicineqSOFA calculator online: rapid sepsis screening outside ICU
Quick bedside assessment of poor outcome risk in suspected infection: 3 criteria – respiratory rate ≥22/min, systolic BP ≤100 mmHg, altered mentation (GCS <15). 2+ points indicate high risk of septic shock and death.
General practice and internal medicinePulmonologyWells Score for Pulmonary Embolism
Pre-test probability of pulmonary embolism using Wells criteria.
PulmonologyCardiologyGeneral practice and internal medicine
Obstetrics and gynecology4
Bishop score calculator online: cervical ripeness before labor induction
Cervical ripeness scoring before labor induction across 5 parameters: dilation, effacement, consistency, position, and fetal station. Guides choice between oxytocin induction, prostaglandins, or cesarean delivery.
Obstetrics and gynecologyOvulation and fertile window calculator
Ovulation date and fertile window from LMP and average cycle length.
Obstetrics and gynecologyGeneral practice and internal medicineFamily medicinePregnancy due date and gestational age
Gestational age and estimated date of delivery from LMP, ultrasound, or IVF transfer date.
Obstetrics and gynecologyGeneral practice and internal medicineFamily medicinePregnancy weight gain calculator online: target ranges by BMI (IOM, 2009)
Recommended pregnancy weight gain by pre-pregnancy BMI per the U.S. Institute of Medicine guideline (IOM, 2009). Supports singleton and twin pregnancies and provides target range and weekly increments.
Obstetrics and gynecologyGeneral practice and internal medicineFamily medicine
Pediatrics and neonatology4
APGAR score for newborns
Standardized newborn assessment across 5 components scored 0–2. Recorded at 1 and 5 minutes after birth.
Pediatrics and neonatologyObstetrics and gynecologyCorrected age for preterm infants
Corrected (postconceptional) age for developmental assessment of preterm infants up to 24 months.
Pediatrics and neonatologyGeneral practice and internal medicineHolliday-Segar 4-2-1 maintenance fluid
Daily and hourly fluid maintenance using the 4-2-1 rule: 100 ml/kg for first 10 kg, 50 ml/kg for next 10, 20 ml/kg beyond.
Pediatrics and neonatologyGeneral practice and internal medicineNephrologyPediatric analgesic dose calculator online: pediatric paracetamol and ibuprofen
Per-dose and daily dose of pediatric paracetamol and ibuprofen by body weight with age limits. Returns dose in mg and mL of standard syrup, maximum daily dose, interval, and contraindications.
Pediatrics and neonatologyGeneral practice and internal medicineFamily medicine
Oncology2
ANC calculator online: absolute neutrophil count and neutropenia severity
Absolute neutrophil count from CBC: ANC = WBC × (% segmented + % bands)/100. Stratifies neutropenia severity and infection risk in patients on chemotherapy and with hematologic conditions.
OncologyGeneral practice and internal medicineBody surface area (BSA) calculator online: DuBois and Mosteller formulas
Body surface area calculation from height and weight for drug dosing in oncology, cardiology, and pediatrics. Supports DuBois (1916) and Mosteller (1987) formulas – both validated in adult and pediatric practice.
OncologyNephrologyCardiology
Psychiatry and addiction medicine2
Blood Alcohol Concentration (Widmark formula)
Theoretical blood alcohol concentration from consumed volume, body mass, sex, and time since drinking. For medical and forensic specialists.
Psychiatry and addiction medicineGeneral practice and internal medicinePHQ-9 calculator online: depression screening and severity questionnaire
PHQ-9 is a 9-item depression screening and severity questionnaire. Each item scored 0–3, total 0–27. Interpretation per DSM-5: none, mild, moderate, moderately severe, severe depression. Used in primary care and patients with chronic conditions.
Psychiatry and addiction medicineGeneral practice and internal medicineFamily medicine
General practice and internal medicine3
Ganzoni formula calculator: iron deficit in mg for anemia treatment
Calculate total iron deficit in mg using the Ganzoni formula (1970). Body weight, actual and target hemoglobin, iron stores – result guides IV or oral iron dosing.
General practice and internal medicineObstetrics and gynecologyGastroenterology and hepatologyIdeal Body Weight (Devine Formula)
Ideal and adjusted body weight for drug dosing.
General practice and internal medicineOncologyNephrologyPhenoAge calculator online: biological age from blood biochemistry (Levine, 2018)
Phenotypic (biological) age from 9 routine biomarkers: albumin, creatinine, glucose, CRP, lymphocytes, MCV, RDW, alkaline phosphatase, white blood cells + chronological age. Validated by Morgan Levine (2018) as a predictor of all-cause and cardiovascular mortality.
General practice and internal medicineFamily medicineEndocrinology