Clinical Calculators

Sorts a metabolic acidosis into high-gap or normal-gap, corrected for albumin. Na − (Cl + HCO3), adjusted to an albumin of 40; normal about 4 to 12 mmol/L.

Weight adjusted for height; screens for underweight and obesity. BMI = weight in kg divided by height in metres squared.

Annual stroke risk in non-valvular AF. 6 items, 0 to 8. Sex-category dropped per 2024 ESC update.

5-item severity score in cirrhosis. 5 to 15, mapped to Class A (well-compensated), B, and C (decompensated).

Estimated GFR from creatinine, age and sex (2021 race-free CKD-EPI). Output mL/min/1.73m2; bands are the CKD stages G1 to G5.

Adjusts the measured total calcium for the albumin level, so a low albumin does not hide a true hypercalcaemia. Corrected calcium = measured calcium + 0.02 x (40 minus albumin in g/L).

Primary-care disposition tool for adult community-acquired pneumonia. 4 items, 0 to 4. Home at 0, hospital at 1 to 2, urgent hospital at 3 to 4.

Disposition tool for adult community-acquired pneumonia. 5 items, 0 to 5. Outpatient at 0 to 1, ward at 2, ICU consideration at 3 to 5.

Bedside conscious state assessment. 3 items (eye, verbal, motor), score 3 to 15.

First once-daily aminoglycoside dose for an adult from lean body weight and creatinine clearance, as eTG calculates it.

Annual major bleeding risk in AF on oral anticoagulation. 9 items, 0 to 9. ≥ 3 flags high risk.

Risk-stratifies adults with undifferentiated chest pain. 5 items, 0 to 10.

The average arterial pressure across a cardiac cycle; the perfusion pressure targeted in shock. MAP = diastolic + (systolic minus diastolic) / 3.

7-item early-warning score for acute illness in adults. 0 to 20. A score of 5+ OR any single parameter at 3 triggers urgent ward review.

Quantifies acute-stroke severity. 15-item exam scored 0 to 42.

Functional severity of heart failure. Class I (no limitation) to IV (symptoms at rest).

9-item depression severity score. 0 to 27. Score ≥ 10 has 88% sensitivity and specificity for major depression. Q9 is a suicide-risk red flag.

3-item bedside sepsis screen for non-ICU patients. 0 to 3. A score of 2 or above flags high mortality risk and prompts full sepsis workup.

Heart-rate-corrects the measured QT interval so it can be compared against the normal range. QTc = QT divided by the square root of the R-R interval in seconds.

10-item pre-test probability score for DVT. -2 to 9. Score 1 or below = DVT unlikely (D-dimer triages), 2 or above = DVT likely (image with US).

7-item pre-test probability score for PE. 0 to 12.5 in 0.5 increments. 4 or below = PE unlikely (D-dimer triages); 4.5 or above = PE likely (image with CTPA).

The difference between alveolar and arterial oxygen; separates hypoxaemia due to shunt/V-Q mismatch from hypoventilation. Rises with age.

8-item clinical and laboratory score for the likelihood of acute appendicitis. 0 to 10.

The circulating neutrophil count that defines neutropenia and its severity. ANC = WCC x neutrophil percent.

Rapid newborn assessment: 5 signs each scored 0-2 (total 0-10), recorded at 1, 5 and 10 minutes.

3-item brief alcohol-use screen. 0 to 12. Score ≥ 4 (men) or ≥ 3 (women) flags hazardous drinking. The "fast triage" before full AUDIT.

Estimated GFR in a child from height and creatinine (2009 bedside Schwartz). Output mL/min/1.73m2.

3-step sequential decision rule for cervical spine imaging in alert blunt-trauma patients. Higher specificity than NEXUS at comparable sensitivity.

5-item primary-care score estimating the probability of GAS pharyngitis. -1 to 5, with age modifier.

10-item nursing-administered score for alcohol withdrawal severity. 0 to 67. Drives symptom-triggered benzodiazepine dosing in admitted patients.

Estimates creatinine clearance for renal drug dosing from age, weight, sex and serum creatinine.

Adjusts the measured sodium for the dilutional effect of a high glucose, so a hyperglycaemic patient is not mistaken for having true hyponatraemia. Corrected sodium = measured sodium + a factor for every mmol/L the glucose is raised.

Global performance status in cancer. 0 (fully active) to 5 (dead). Guides treatment fitness and prognosis.

7-item anxiety severity score. 0 to 21. Score ≥ 10 has 89% sensitivity and 82% specificity for GAD.

A 15-item yes/no depression screen validated in older adults. Score 0 to 15; 5 or more suggests depression.

8-item pre-endoscopic risk score for adults with suspected UGIB. 0 to 23. Score 0 enables outpatient management.

In-hospital and 6-month mortality risk in ACS. 8 inputs, 0 to ~370. > 140 favours early invasive strategy.

3-stage AKI severity by creatinine or urine output, whichever is worse. Stage 0 to Stage 3.

Fat-free weight from sex, height and weight: the weight eTG doses aminoglycosides on in adults.

Classifies a pleural effusion as exudate or transudate; an exudate is flagged if any one of three ratios is exceeded.

Hourly maintenance IV fluid rate by weight (the 4-2-1 rule). Not a resuscitation volume.

3-month mortality and transplant-priority score in chronic liver disease. Composite formula on bilirubin, creatinine, INR and sodium; 6 to 40.

Estimates a child's genetic height potential from the biological parents' heights, and shows whether the child's predicted adult height falls inside the expected family range. Girl = (mother + father - 13) / 2; boy = (mother + father + 13) / 2, with a target range of 8.5 cm either side.

Single-question 7-level scale of post-stroke disability. 0 (no symptoms) to 6 (dead). The standard functional outcome measure in stroke trials and clinical follow-up.

5-item rule-out for cervical spine imaging in blunt trauma. All criteria absent = clinical clearance, no imaging needed.

Screens for an unmeasured osmole such as a toxic alcohol. Measured osmolality minus calculated (2 x Na + urea + glucose); a gap above about 10 is raised.

5-criterion rule-out for ankle and midfoot imaging in acute injury. All criteria absent = clinical clearance, no x-ray needed.

5-criterion rule-out for knee imaging in acute injury. All criteria absent = clinical clearance, no x-ray needed.

Lifetime cigarette exposure, used to estimate the risk of smoking-related disease and to check eligibility for lung cancer screening. Pack-years = (cigarettes per day divided by 20) x years smoked.

Decides whether a child with minor head injury needs a CT, observation, or neither, by age-stratified predictors.

8-criterion rule-out for PE in low-pre-test-probability patients. All 8 absent = PE ruled out, no D-dimer needed.

20-item mortality risk score for adult CAP. Two-stage: Class I by criteria, Classes II to V by points. The most-validated CAP severity tool.

Bedside screen for acute stroke in the ED. 7 items, scored -2 to +5.

A non-invasive surrogate for the PaO2/FiO2 ratio, grading hypoxaemia and ARDS severity without an arterial gas.

Heart rate divided by systolic blood pressure, banded to flag the compensated patient whose blood pressure still looks normal.

6-organ-system ICU score quantifying organ dysfunction. 0 to 24. The full Sepsis-3 companion to qSOFA.

8-item screen for obstructive sleep apnoea. 0 to 8. A score of 5 or more flags high risk of moderate-severe OSA.

14-day risk of death, MI, or urgent revascularisation in NSTE-ACS. 7 items, 0 to 7.