Clinical Calculators
Clinical calculators & scores
Fast, free and ad-free. 128 evidence-led tools with instant, risk-stratified interpretation and references — built to a clinical-safety standard.
CHA₂DS₂-VASc Score
Stroke risk in atrial fibrillation, guiding anticoagulation.
Open calculator → CardiologyHAS-BLED Score
Major bleeding risk on anticoagulation in atrial fibrillation.
Open calculator → CardiologyMean Arterial Pressure (MAP)
Average arterial pressure across the cardiac cycle.
Open calculator → Emergency MedicineCURB-65 Score
Severity and mortality risk in community-acquired pneumonia.
Open calculator → Critical CareqSOFA Score
Quick bedside flag for poor outcome in suspected infection.
Open calculator → Acute MedicineNEWS2 (National Early Warning Score 2)
Standardised UK early-warning score for acute illness.
Open calculator → NeurologyGlasgow Coma Scale (GCS)
Level of consciousness from eye, verbal and motor response.
Open calculator → Emergency MedicineWells Score for DVT
Pre-test probability of deep vein thrombosis.
Open calculator → NephrologyCreatinine Clearance (Cockcroft-Gault)
Estimated creatinine clearance for drug dosing.
Open calculator → ChemistryCorrected Calcium
Albumin-adjusted total calcium.
Open calculator → ChemistryAnion Gap
Serum anion gap for metabolic acidosis.
Open calculator → GeneralBody Mass Index (BMI)
Weight-for-height screening measure.
Open calculator → CardiologyCHADS₂ Score
Older stroke-risk score in atrial fibrillation.
Open calculator → Emergency MedicineWells Score for PE
Pre-test probability of pulmonary embolism.
Open calculator → Emergency MedicinePERC Rule
Rules out PE in low-risk patients when all criteria are absent.
Open calculator → CardiologyHEART Score
Risk of major adverse cardiac event in chest pain.
Open calculator → Primary CareCentor Score (McIsaac modified)
Likelihood of streptococcal pharyngitis.
Open calculator → HaematologyPadua Prediction Score
VTE risk in hospitalised medical patients.
Open calculator → NephrologyeGFR (CKD-EPI 2021)
Estimated GFR, race-free creatinine equation.
Open calculator → GeneralIdeal Body Weight (Devine)
Ideal body weight from height and sex.
Open calculator → HepatologyMELD Score
Severity of end-stage liver disease.
Open calculator → HepatologyFIB-4 Index
Non-invasive estimate of liver fibrosis.
Open calculator → ObstetricsBishop Score
Cervical favourability for induction of labour.
Open calculator → Emergency MedicineParkland Formula (Burns)
24-hour fluid resuscitation in burns.
Open calculator → PaediatricsPaediatric Maintenance Fluid
Daily maintenance fluid in children by weight (Holliday-Segar).
Open calculator → PaediatricsAPGAR Score
Rapid assessment of newborn condition after birth.
Open calculator → Emergency MedicineAlvarado Score
Likelihood of acute appendicitis.
Open calculator → HepatologyChild-Pugh Score
Severity and prognosis of chronic liver disease.
Open calculator → PsychiatryPHQ-9 (Depression)
Severity of depressive symptoms.
Open calculator → PsychiatryGAD-7 (Anxiety)
Severity of generalised anxiety symptoms.
Open calculator → NeurologyABCD² Score
Early stroke risk after TIA.
Open calculator → CardiologyTIMI Risk Score (UA/NSTEMI)
14-day risk of adverse events in unstable angina/NSTEMI.
Open calculator → CardiologyCorrected QT (QTc, Bazett)
Heart-rate-corrected QT interval.
Open calculator → ChemistryWinters' Formula
Expected pCO₂ in metabolic acidosis.
Open calculator → NephrologyFractional Excretion of Sodium (FENa)
Distinguishes pre-renal from intrinsic AKI.
Open calculator → HepatologyMaddrey's Discriminant Function
Severity of alcoholic hepatitis.
Open calculator → EndocrinologyHbA1c to Average Glucose
Estimated average glucose from HbA1c.
Open calculator → Critical CareSIRS Criteria
Systemic inflammatory response syndrome.
Open calculator → Haematology4Ts Score for HIT
Probability of heparin-induced thrombocytopenia.
Open calculator → Primary CareAUDIT-C (Alcohol Use)
Screen for hazardous drinking.
Open calculator → Primary CareCAGE Questionnaire
Brief screen for problem drinking.
Open calculator → Emergency MedicinePESI (PE Severity Index)
30-day mortality risk in pulmonary embolism.
Open calculator → GastroenterologyRockall Score (pre-endoscopy)
Risk after upper GI bleeding (clinical score).
Open calculator → GastroenterologyGlasgow-Blatchford Score
Risk stratification of upper GI bleeding.
Open calculator → EndocrinologyHOMA-IR
Estimate of insulin resistance.
Open calculator → ChemistryCalculated Serum Osmolality
Estimated osmolality from electrolytes.
Open calculator → GeneralBody Surface Area (Mosteller)
BSA from height and weight.
Open calculator → NephrologyFree Water Deficit
Estimated water deficit in hypernatraemia.
Open calculator → Critical CareSOFA Score
Sequential organ failure assessment.
Open calculator → Emergency MedicineRevised Geneva Score (PE)
Pre-test probability of PE (objective).
Open calculator → AnaestheticsApfel Score (PONV)
Risk of postoperative nausea and vomiting.
Open calculator → Acute MedicineMEWS (Modified Early Warning Score)
Older early-warning score (NEWS2 now preferred in the UK).
Open calculator → PulmonologyLight's Criteria
Distinguishes exudative from transudative effusions.
Open calculator → HaematologyMASCC Score
Risk in febrile neutropenia (higher = lower risk).
Open calculator → Emergency MedicineShock Index
Heart rate divided by systolic BP.
Open calculator → HaematologyMentzer Index
Thalassaemia trait vs iron-deficiency anaemia.
Open calculator → HepatologyMELD-Na Score
MELD adjusted for serum sodium.
Open calculator → NephrologyTranstubular Potassium Gradient (TTKG)
Assesses renal potassium handling.
Open calculator → PulmonologyA-a Gradient
Alveolar-arterial oxygen gradient (kPa).
Open calculator → GastroenterologyGlasgow-Imrie Score (Pancreatitis)
Severity of acute pancreatitis (PANCREAS).
Open calculator → GastroenterologyRanson Criteria (admission)
Early severity markers in acute pancreatitis.
Open calculator → Primary CareFeverPAIN Score
Likelihood of streptococcal sore throat.
Open calculator → PulmonologySTOP-BANG Score
Screen for obstructive sleep apnoea.
Open calculator → Geriatrics4AT (Delirium Screen)
Rapid bedside test for delirium.
Open calculator → NeurologyModified Rankin Scale (mRS)
Degree of disability after stroke.
Open calculator → EndocrinologyBurch-Wartofsky Score
Likelihood of thyroid storm.
Open calculator → RheumatologyDAS28-ESR
Rheumatoid arthritis disease activity.
Open calculator → CardiologyCorrected QT (QTc, Fridericia)
Cube-root heart-rate correction of QT.
Open calculator → NephrologyFractional Excretion of Urea (FEUrea)
Pre-renal vs intrinsic AKI (useful on diuretics).
Open calculator → HaematologyCorrected Reticulocyte Count
Reticulocyte count adjusted for anaemia.
Open calculator → CardiologyNYHA Functional Class
Functional severity of heart failure.
Open calculator → OncologyECOG Performance Status
Functional status in oncology.
Open calculator → PulmonologymMRC Dyspnoea Scale
Breathlessness severity in COPD.
Open calculator → CardiologyKillip Classification
Heart failure severity in acute MI.
Open calculator → GeriatricsAbbreviated Mental Test Score (AMTS)
Brief screen for cognitive impairment.
Open calculator → GeriatricsBarthel Index (ADL)
Independence in activities of daily living.
Open calculator → PaediatricsWestley Croup Score
Severity of croup in children.
Open calculator → Emergency MedicineNEXUS C-Spine Criteria
Whether cervical-spine imaging can be avoided.
Open calculator → CardiologySgarbossa Criteria
Diagnosing MI in left bundle branch block.
Open calculator → PulmonologyDECAF Score
Mortality risk in COPD exacerbation.
Open calculator → HaematologyTransferrin Saturation
Iron status from serum iron and TIBC.
Open calculator → NeurologyNIHSS (Stroke Severity)
National Institutes of Health Stroke Scale.
Open calculator → Addiction MedicineCIWA-Ar (Alcohol Withdrawal)
Severity of alcohol withdrawal.
Open calculator → Emergency MedicineOttawa Ankle Rules
Whether ankle/foot X-rays are needed after injury.
Open calculator → GeriatricsClinical Frailty Scale (Rockwood)
Degree of frailty in older adults.
Open calculator → NursingBraden Scale (Pressure Ulcer)
Risk of developing a pressure ulcer (lower = higher risk).
Open calculator → NursingMorse Fall Scale
Risk of falling in hospital.
Open calculator → PsychiatryEPDS (Postnatal Depression)
Edinburgh Postnatal Depression Scale.
Open calculator → PsychiatryPHQ-2 (Depression Screen)
Two-item depression screen.
Open calculator → PsychiatryGAD-2 (Anxiety Screen)
Two-item anxiety screen.
Open calculator → HepatologyGlasgow Alcoholic Hepatitis (GAHS)
Prognosis in alcoholic hepatitis (GAHS).
Open calculator → ChemistrySodium Correction for Hyperglycaemia
Corrected sodium in hyperglycaemia (Katz).
Open calculator → Emergency MedicineOttawa Knee Rule
Whether a knee X-ray is needed after injury.
Open calculator → Primary CareCRB-65 Score
Community pneumonia severity (no bloods needed).
Open calculator → PulmonologyPSI / PORT Score (Pneumonia)
30-day mortality risk in community pneumonia.
Open calculator → GastroenterologyAIMS65 Score
Mortality risk in upper GI bleeding.
Open calculator → Critical CareFOUR Score (Coma)
Full Outline of UnResponsiveness — coma severity.
Open calculator → Critical CareRASS (Sedation–Agitation)
Richmond Agitation–Sedation Scale.
Open calculator → Critical CareROX Index
Predicts high-flow nasal oxygen success.
Open calculator → Critical CareP/F Ratio (PaO₂/FiO₂)
Oxygenation; ARDS severity (Berlin).
Open calculator → NeurologyCorrected Phenytoin (Sheiner-Tozer)
Albumin-adjusted phenytoin level.
Open calculator → ChemistryDelta Ratio (Acid–Base)
Detects mixed metabolic acid–base disorders.
Open calculator → PulmonologyBODE Index (COPD)
Prognosis in COPD.
Open calculator → NephrologySodium Deficit (Hyponatraemia)
Estimated sodium needed to reach a target.
Open calculator → GastroenterologyBISAP Score (Pancreatitis)
Early mortality risk in acute pancreatitis.
Open calculator → HepatologyAPRI (AST–Platelet Ratio)
Non-invasive estimate of liver fibrosis.
Open calculator → HepatologyNAFLD Fibrosis Score
Advanced fibrosis risk in fatty liver disease.
Open calculator → CardiologySAMe-TT₂R₂ Score
Predicts anticoagulation control on warfarin.
Open calculator → CardiologyORBIT Bleeding Score
Bleeding risk on anticoagulation in AF.
Open calculator → Emergency MedicineCanadian CT Head Rule
Whether CT is needed after minor head injury.
Open calculator → RheumatologyDAS28-CRP
Rheumatoid arthritis activity (CRP version).
Open calculator → HepatologySAAG (Ascites)
Serum–ascites albumin gradient.
Open calculator → ChemistryOsmolar Gap
Measured minus calculated osmolality.
Open calculator → CardiologyCorrected QT (QTc, Hodges)
Linear heart-rate correction of QT.
Open calculator → HaematologyCaprini VTE Risk Score
VTE risk in surgical patients.
Open calculator → Critical CareAPACHE II Score
ICU severity of illness and mortality risk.
Open calculator → PaediatricsSchwartz eGFR (Paediatric)
Estimated GFR in children (bedside Schwartz).
Open calculator → ChemistryAlbumin-Corrected Anion Gap
Anion gap adjusted for low albumin.
Open calculator → HaematologyIron Deficit (Ganzoni)
Total iron deficit for replacement.
Open calculator → GeneralAdjusted Body Weight
Dosing weight in obesity.
Open calculator → Primary CarePack-Years (Smoking)
Cumulative tobacco exposure.
Open calculator → HepatologyR Factor (Liver Injury Pattern)
Hepatocellular vs cholestatic injury.
Open calculator → CardiologyCHA₂DS₂-VA Score
Stroke risk in AF (2024, sex removed).
Open calculator → Addiction MedicineAUDIT (Alcohol Use)
Full 10-item alcohol-use disorders test.
Open calculator → PulmonologySMART-COP (Pneumonia)
Predicts need for intensive respiratory/vasopressor support.
Open calculator → HaematologyReticulocyte Production Index (RPI)
Marrow response corrected for anaemia and maturation.
Open calculator → EndocrinologyCorticosteroid Dose Converter
Glucocorticoid equivalence to prednisolone.
Open calculator → GeneralEstimated Blood Volume (Nadler)
Total blood volume from height, weight and sex.
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