77 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.
10-year risk of first MI, fatal CHD or stroke from the AHA/ACC 2013 Pooled Cohort Equations. Ages 40–79.
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.
In-hospital mortality risk in acute coronary syndrome from 8 parameters. Used to select timing of invasive strategy.
Bleeding risk in patients on anticoagulation. Used alongside CHA₂DS₂-VASc.
6-week MACE risk in chest-pain patients from five domains: history, ECG, age, risk factors, troponin.
Determine Killip class in acute MI: I–IV by symptoms with 30-day mortality from GUSTO-I.
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.
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.
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.
10-year risk of fatal and non-fatal CVD events in adults 40–69, calibrated for four European risk regions.
30-day mortality estimate in confirmed pulmonary embolism, used to decide between outpatient and inpatient management.
14-day risk of death, MI, or severe ischemia in non-ST-elevation ACS using 7 criteria.
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.
Two-day ischemic stroke risk after transient ischemic attack.
Consciousness level by eye opening, verbal response, and motor response. Total range 3–15.
Enter the total MMSE score 0–30 to receive an interpretation with low-education correction.
Enter the total MoCA score 0–30 to receive an interpretation with a +1 bonus for ≤12 years of education.
Standardized 15-item assessment of ischemic stroke severity. Total range 0–42.
Compute albumin-corrected anion gap in hypoalbuminaemia: AG + 2.5 × (4 − albumin).
Serum calcium corrected for albumin concentration.
Anion gap calculation for differential diagnosis of metabolic acidosis.
Creatinine clearance for drug dose adjustment. Not equivalent to eGFR.
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.
Estimate free water deficit in hypernatraemia: weight × TBW factor × (Na/140 − 1).
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.
Estimate in-hospital mortality risk for upper GI bleeding with 5 AIMS65 criteria: albumin, INR, mental status, BP, age.
Assess acute pancreatitis severity with the 5 BISAP criteria: BUN, mental status, SIRS, age, pleural effusion.
Liver cirrhosis severity and survival prognosis assessment.
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.
Severity stratification for upper GI bleeding to guide admission and timing of endoscopy.
Severity of acute alcoholic hepatitis based on prothrombin time and bilirubin. A score ≥ 32 indicates severe disease.
Chronic liver disease severity and 90-day mortality prognosis.
Three-month mortality prediction in cirrhosis adjusted for serum sodium. Used by UNOS / OPTN since 2016 for liver allocation.
Acute pancreatitis severity scored at admission and 48 hours later. A score ≥ 3 indicates moderate-to-severe disease.
Body fat percentage from neck, waist, and hip circumferences. Validated against hydrostatic weighing.
Body mass index from height and weight with WHO classification.
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.
Conversion of HbA1c to average plasma glucose using ADAG equations. Supports NGSP (%) and IFCC (mmol/mol) units.
Weight range by BMI 18.5–24.9 (WHO) plus Devine and Hamwi ideal body weight for drug dosing.
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).
Resting metabolic rate and total daily energy expenditure by activity level. Most accurate formula for adults per ADA Evidence Analysis.
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.
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.
Daytime sleepiness measured as likelihood of dozing in eight typical situations. Total 0–24.
Stratify community-acquired pneumonia severity by 20 PSI/PORT items: classes I–V with 30-day mortality.
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.
Eight-item screen for obstructive sleep apnea. A score ≥ 5 means high risk of moderate-to-severe OSA.
Pre-test probability of pulmonary embolism using Wells criteria.
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.
Ovulation date and fertile window from LMP and average cycle length.
Gestational age and estimated date of delivery from LMP, ultrasound, or IVF transfer date.
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.
Standardized newborn assessment across 5 components scored 0–2. Recorded at 1 and 5 minutes after birth.
Corrected (postconceptional) age for developmental assessment of preterm infants up to 24 months.
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.
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.
Absolute neutrophil count from CBC: ANC = WBC × (% segmented + % bands)/100. Stratifies neutropenia severity and infection risk in patients on chemotherapy and with hematologic conditions.
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.
VTE risk in ambulatory cancer patients before starting systemic chemotherapy.
Three-question WHO AUDIT subset for problem-drinking screening. Total 0–12; cutoff ≥ 4 in men, ≥ 3 in women.
Theoretical blood alcohol concentration from consumed volume, body mass, sex, and time since drinking. For medical and forensic specialists.
Assess alcohol withdrawal severity with the 10-item CIWA-Ar: 0–67 points with thresholds at 10 and 20.
Six questions assessing nicotine dependence severity and guiding pharmacologic support for smoking cessation.
Screening and severity grading of generalized anxiety disorder over the last 2 weeks. Total 0–21.
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.
Perioperative VTE risk score guiding the choice of thromboprophylaxis in surgical patients.
Probability of group A streptococcal pharyngitis to guide testing and antibiotic decisions.
Correct serum sodium for hyperglycaemia: Hillier formula with 2.4 factor per 5.6 mmol/L glucose above normal.
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.
Convert any glucocorticoid dose to equivalents of any other: hydrocortisone, prednisone, methylprednisolone, dexamethasone.
Ideal and adjusted body weight for drug dosing.
Differentiates microcytic anemia: beta-thalassemia trait vs iron deficiency from MCV and RBC count.
Convert any opioid daily dose to morphine milligram equivalents (MME/day) with CDC 2022 risk category.
Standardized severity assessment based on seven vital parameters. Used in wards and EDs to detect early deterioration.
VTE risk stratification for medical inpatients. A total of ≥ 4 points indicates the need for anticoagulant prophylaxis.
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.