Clinical scale calculators
109 scales and formulas with links to the original publications
Popular
Cardiology
- ABI
Ankle-brachial index (ABI)
Ratio of ankle to brachial pressure. Below 0.90 confirms peripheral artery disease, above 1.40 indicates calcification.
- ASCVD
ASCVD 10-year risk (Pooled Cohort Equations)
10-year risk of first MI, fatal CHD or stroke from the AHA/ACC 2013 Pooled Cohort Equations. Ages 40–79.
- CHA₂DS₂-VA
CHA₂DS₂-VA, thromboembolic risk in atrial fibrillation
The ESC 2024 version without the sex category: maximum 8 points. Anticoagulation is recommended from 2 points.
- CHA₂DS₂-VASc
CHA₂DS₂-VASc calculator
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.
- GRACE 2.0
GRACE 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.
- HAS-BLED
HAS-BLED (Bleeding Risk on Anticoagulation)
Bleeding risk in patients on anticoagulation. Used alongside CHA₂DS₂-VASc.
- HEART
HEART Score (chest pain in the emergency department)
6-week MACE risk in chest-pain patients from five domains: history, ECG, age, risk factors, troponin.
Killip class calculator
Determine Killip class in acute MI: I–IV by symptoms with 30-day mortality from GUSTO-I.
- LDL
LDL Friedewald calculator
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.
- MAP
MAP calculator
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.
- QTc
QTc Bazett calculator
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.
- RCRI
RCRI, Revised Cardiac Risk Index for noncardiac surgery
Six predictors, 1 point each. Gives the rate of a major cardiac event after noncardiac surgery.
- SCORE2
SCORE2 (10-year cardiovascular risk for Europe)
10-year risk of fatal and non-fatal CVD events in adults 40–69, calibrated for four European risk regions.
- SCORE2-OP
SCORE2-OP
10-year cardiovascular risk from age 70. Accounts for the competing risk of non-cardiovascular death.
- sPESI
sPESI (Simplified Pulmonary Embolism Severity Index)
30-day mortality estimate in confirmed pulmonary embolism, used to decide between outpatient and inpatient management.
- TIMI
TIMI Risk Score for UA/NSTEMI
14-day risk of death, MI, or severe ischemia in non-ST-elevation ACS using 7 criteria.
Warfarin dose calculator (IWPC 2009 algorithm)
Warfarin maintenance dose from the IWPC 2009 equation, the anchor for choosing a starting dose: age, height, weight, VKORC1 and CYP2C9, amiodarone. Then INR.
Wells score for DVT
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.
Neurology
- ABCD²
ABCD² Score (stroke risk after TIA)
Two-day ischemic stroke risk after transient ischemic attack.
- GCS
Glasgow Coma Scale (GCS)
Consciousness level by eye opening, verbal response, and motor response. Total range 3–15.
- MMSE
MMSE calculator
Enter the total MMSE score 0–30 to receive an interpretation with low-education correction.
- MoCA
MoCA calculator
Enter the total MoCA score 0–30 to receive an interpretation with a +1 bonus for ≤12 years of education.
- mRS
Modified Rankin Scale (mRS)
Functional outcome after stroke on a single 0 to 6 grade. A score of 0 to 2 is usually treated as a favourable outcome.
- NIHSS
NIH Stroke Scale (NIHSS)
Standardized 15-item assessment of ischemic stroke severity. Total range 0–42.
Nephrology
- Adrogue-Madias
Adrogue-Madias formula calculator
Estimate the serum sodium change from 1 litre of fluid with the Adrogue-Madias formula: (infusate Na+K − serum Na) / (TBW + 1).
Albumin-corrected anion gap calculator
Compute albumin-corrected anion gap in hypoalbuminaemia: AG + 2.5 × (4 − albumin).
Albumin-Corrected Calcium
Serum calcium corrected for albumin concentration.
Anion Gap (Albumin-Corrected)
Anion gap calculation for differential diagnosis of metabolic acidosis.
- Cockcroft-Gault
Creatinine Clearance (Cockcroft-Gault)
Creatinine clearance for drug dose adjustment. Not equivalent to eGFR.
- eGFR
eGFR calculator
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.
Free water deficit calculator for hypernatraemia
Estimate free water deficit in hypernatraemia: weight × TBW factor × (Na/140 − 1).
Serum osmolality calculator
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.
Gastroenterology and hepatology
- AIMS65
AIMS65 calculator
Estimate in-hospital mortality risk for upper GI bleeding with 5 AIMS65 criteria: albumin, INR, mental status, BP, age.
- BISAP
BISAP calculator
Assess acute pancreatitis severity with the 5 BISAP criteria: BUN, mental status, SIRS, age, pleural effusion.
- Child-Pugh
Child-Pugh Score (Liver Cirrhosis)
Liver cirrhosis severity and survival prognosis assessment.
- FIB-4
FIB-4 calculator
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.
Glasgow-Blatchford Score (upper GI bleeding severity)
Severity stratification for upper GI bleeding to guide admission and timing of endoscopy.
Maddrey Discriminant Function (alcoholic hepatitis severity)
Severity of acute alcoholic hepatitis based on prothrombin time and bilirubin. A score ≥ 32 indicates severe disease.
- MELD
MELD Score (Liver Disease)
Chronic liver disease severity and 90-day mortality prognosis.
- MELD-Na
MELD-Na (Model for End-Stage Liver Disease with sodium)
Three-month mortality prediction in cirrhosis adjusted for serum sodium. Used by UNOS / OPTN since 2016 for liver allocation.
Ranson Criteria (acute pancreatitis severity)
Acute pancreatitis severity scored at admission and 48 hours later. A score ≥ 3 indicates moderate-to-severe disease.
Endocrinology
Body fat percentage (US Navy method)
Body fat percentage from neck, waist, and hip circumferences. Validated against hydrostatic weighing.
- BMI
Body Mass Index (BMI)
Body mass index from height and weight with WHO classification.
- FINDRISC
FINDRISC calculator
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.
- eAG
HbA1c → estimated average glucose (eAG)
Conversion of HbA1c to average plasma glucose using ADAG equations. Supports NGSP (%) and IFCC (mmol/mol) units.
Healthy weight range
Weight range by BMI 18.5–24.9 (WHO) plus Devine and Hamwi ideal body weight for drug dosing.
- HOMA-IR
HOMA-IR calculator
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 (Mifflin-St Jeor) + TDEE
Resting metabolic rate and total daily energy expenditure by activity level. Most accurate formula for adults per ADA Evidence Analysis.
- SCORE2-Diabetes
SCORE2-Diabetes
10-year cardiovascular risk in type 2 diabetes at ages 40-69. Includes age at diagnosis, HbA1c and eGFR.
Semaglutide dose escalation schedule (Ozempic, Wegovy, Rybelsus)
Semaglutide escalation schedule from the AEMPS ficha tecnica: weeks and steps for Ozempic, Wegovy and Rybelsus, minimum intervals, missed dose rules.
Weight loss calorie calculator
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.
Pulmonology
- BODE
BODE index in COPD
Four components: body mass index, FEV1, mMRC dyspnoea and the six-minute walk test. Total 0-10, split into quartiles.
- CURB-65
CURB-65 calculator
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.
- ESS
Epworth Sleepiness Scale (ESS)
Daytime sleepiness measured as likelihood of dozing in eight typical situations. Total 0–24.
- mMRC
mMRC dyspnoea scale
Five grades from 0 to 4. GOLD treats 2 points as the threshold for a high symptom burden.
- PSI
PSI/PORT calculator
Stratify community-acquired pneumonia severity by 20 PSI/PORT items: classes I–V with 30-day mortality.
- qSOFA
qSOFA calculator
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.
- STOP-BANG
STOP-BANG Questionnaire (OSA screening)
Eight-item screen for obstructive sleep apnea. A score ≥ 5 means high risk of moderate-to-severe OSA.
Wells Score for Pulmonary Embolism
Pre-test probability of pulmonary embolism using Wells criteria.
Obstetrics and gynecology
Bishop score calculator
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 and fertile window calculator
Ovulation date and fertile window from LMP and average cycle length.
Pregnancy due date and gestational age
Gestational age and estimated date of delivery from LMP, ultrasound, or IVF transfer date.
Pregnancy weight gain calculator
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.
Pediatrics and neonatology
- APGAR
APGAR score for newborns
Standardized newborn assessment across 5 components scored 0–2. Recorded at 1 and 5 minutes after birth.
Corrected age for preterm infants
Corrected (postconceptional) age for developmental assessment of preterm infants up to 24 months.
Feeding interval after a maternal dose
How many hours after a single dose the maternal plasma concentration falls to roughly 3 % of peak. Derived from time to peak and the elimination half-life.
- Holliday-Segar
Holliday-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.
Pediatric analgesic dose calculator
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.
- RID
Relative Infant Dose (RID)
The share of the weight-adjusted maternal dose an infant receives through milk. Hale thresholds: under 10 % usually compatible, over 25 % usually avoided.
Oncology
- ANC
ANC calculator
Absolute neutrophil count from CBC: ANC = WBC × (% segmented + % bands)/100. Stratifies neutropenia severity and infection risk in patients on chemotherapy and with hematologic conditions.
- BSA
Body surface area (BSA) calculator
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.
Khorana Score (VTE risk in cancer patients starting chemotherapy)
VTE risk in ambulatory cancer patients before starting systemic chemotherapy.
Psychiatry and addiction medicine
- AUDIT-C
AUDIT-C (brief alcohol screening)
Three-question WHO AUDIT subset for problem-drinking screening. Total 0–12; cutoff ≥ 4 in men, ≥ 3 in women.
Blood Alcohol Concentration (Widmark formula)
Theoretical blood alcohol concentration from consumed volume, body mass, sex, and time since drinking. For medical and forensic specialists.
- CIWA-Ar
CIWA-Ar calculator
Assess alcohol withdrawal severity with the 10-item CIWA-Ar: 0–67 points with thresholds at 10 and 20.
Fagerström Test for Nicotine Dependence
Six questions assessing nicotine dependence severity and guiding pharmacologic support for smoking cessation.
- GAD-7
GAD-7 (Generalized Anxiety Disorder 7-item scale)
Screening and severity grading of generalized anxiety disorder over the last 2 weeks. Total 0–21.
- PHQ-9
PHQ-9 calculator
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.
General practice and internal medicine
Barthel Index
Basic activities of daily living across ten items, 0 to 100 points. Baztán thresholds: under 20 total dependence, 100 independence.
Caprini Risk Assessment Model (perioperative VTE risk)
Perioperative VTE risk score guiding the choice of thromboprophylaxis in surgical patients.
Caregiver Strain Index
Thirteen yes-or-no questions put to the caregiver. The high-strain threshold is 7 points out of 13.
Centor / McIsaac Criteria (streptococcal pharyngitis)
Probability of group A streptococcal pharyngitis to guide testing and antibiotic decisions.
Charlson Comorbidity Index
Weighted sum of comorbid conditions with an age adjustment. Yields an estimate of ten-year survival.
Corrected sodium for hyperglycaemia calculator (Hillier formula)
Correct serum sodium for hyperglycaemia: Hillier formula with 2.4 factor per 5.6 mmol/L glucose above normal.
Downton Fall Risk Index
Fall risk across five blocks, maximum 11 points. High-risk threshold: 3 points or more.
- EMINA
EMINA scale
Five parameters scored 0-3: mental state, mobility, incontinence, nutrition, activity. Total 0-15, the higher the greater the risk.
Ganzoni formula calculator
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.
- GDS-15
Geriatric Depression Scale, 15-item (GDS-15)
Fifteen yes-or-no questions with no somatic items. Screening threshold 5 points.
Glucocorticoid equivalent dose calculator
Convert any glucocorticoid dose to equivalents of any other: hydrocortisone, prednisone, methylprednisolone, dexamethasone.
Goldberg Anxiety and Depression Scale
Two nine-item subscales with a screening filter of the first four questions. Thresholds: anxiety 4 points, depression 2 points.
Ideal Body Weight (Devine Formula)
Ideal and adjusted body weight for drug dosing.
- IPSS
IPSS, International Prostate Symptom Score
Seven questions scored 0-5 on lower urinary tract symptoms, plus a separate quality-of-life question.
- Lawton-Brody
Lawton-Brody IADL Scale
Instrumental activities of daily living: eight items scored 0 or 1. Complements the Barthel Index at the upper end of function.
Mentzer Index (microcytic anemia)
Differentiates microcytic anemia: beta-thalassemia trait vs iron deficiency from MCV and RBC count.
- MME
MME calculator
Convert any opioid daily dose to morphine milligram equivalents (MME/day) with CDC 2022 risk category.
- MUST
MUST, Malnutrition Universal Screening Tool
Three steps: body mass index, unplanned weight loss over 3-6 months and acute illness with no intake. Total 0 to 6.
- NEWS2
NEWS2 (National Early Warning Score 2)
Standardized severity assessment based on seven vital parameters. Used in wards and EDs to detect early deterioration.
Norton Scale
Pressure ulcer risk across five parameters scored 1 to 4. The lower the total, the higher the risk: 14 or below indicates risk.
Padua Prediction Score (VTE risk in hospitalized medical patients)
VTE risk stratification for medical inpatients. A total of ≥ 4 points indicates the need for anticoagulant prophylaxis.
Pfeiffer Short Portable Mental Status Questionnaire
Ten-question cognitive screen. Errors are counted and the threshold shifts with an education adjustment.
- PhenoAge
PhenoAge calculator
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.
- POMA
Tinetti Performance-Oriented Mobility Assessment (POMA)
Observed balance and gait, 16 and 12 points. Below 19 of 28 indicates high fall risk.
Emergency medicine
- 4Ts
4Ts score for heparin-induced thrombocytopenia
Four features scored 0-2: degree of thrombocytopenia, timing, thrombosis, other causes. Total 0-8.
Alvarado score
Probability of acute appendicitis across eight findings, maximum 10 points. Mnemonic MANTRELS.
- APACHE II
APACHE II
Severity of illness in intensive care: 12 physiological variables, age and chronic health. Maximum 71 points.
Parkland formula
First-day fluid volume after a burn: 4 mL × weight × percent body surface. Half goes in over the first 8 hours from the burn.
- PERC
PERC rule calculator
Check the 8 PERC criteria to rule out PE without a D-dimer when pretest probability is low.
- SOFA
SOFA, Sequential Organ Failure Assessment
Six organ systems scored 0-4, maximum 24. Under Sepsis-3, sepsis is defined by a rise of 2 points from baseline.